JP5956742B2 - Photoelectric conversion element - Google Patents

Description

  The present invention relates to a photoelectric conversion element.

  Back-contact solar cells are designed to improve the conversion efficiency by increasing the amount of received light by eliminating the shadow caused by the electrodes on the light receiving surface side by forming the pn junction and the electrode on the back surface side that were conventionally on the light receiving surface side. It is.

  As a method for forming a pn junction, a method of depositing p-type amorphous silicon and n-type amorphous silicon on the back surface of crystalline silicon by plasma CVD (Chemical Vapor Deposition) is known (Patent Document 1).

JP 2010-80887 A

  However, in the solar cell described in Patent Document 1, since the end face of single crystal silicon where electrons and holes are photoexcited is not covered with amorphous silicon, the recombination loss of carriers at the end face of single crystal silicon There is a problem that the remarkably increases.

  Accordingly, the present invention has been made to solve such a problem, and provides a photoelectric conversion element capable of improving the conversion efficiency.

A photoelectric conversion element according to an embodiment of the present invention includes a single crystal silicon substrate and first and second amorphous films. The single crystal silicon substrate has the first conductivity type. The first amorphous film is provided in contact with the surface of the single crystal silicon substrate on the side opposite to the light incident side of the single crystal silicon substrate, and has a second conductivity type opposite to the first conductivity type, And at least the film | membrane which consists of an amorphous phase is included. The second amorphous film is adjacent to the first amorphous film in the in-plane direction of the single crystal silicon substrate in a cross-sectional view in which a plurality of the first amorphous films are arranged on the cut surface. The single crystal silicon substrate is provided in contact with the surface opposite to the light incident side and the end surface of the single crystal silicon substrate, has the first conductivity type, and is made of an amorphous phase.

  In the photoelectric conversion element according to the embodiment of the present invention, the surface of the single crystal silicon substrate opposite to the light incident side is covered with the first and second amorphous films, and the end surface of the single crystal silicon substrate is Covered by the second amorphous film. As a result, one of the carriers (electrons and holes) photoexcited in the single crystal silicon substrate is caused to pass through the single crystal silicon substrate and the first amorphous by the passivation effect of the single crystal silicon substrate by the first amorphous film. Recombination at the interface with the film is suppressed and the first amorphous film is easily reached, and the other of the photoexcited carriers (electrons and holes) in the single crystal silicon substrate is the second amorphous film. Due to the passivation effect of the single crystal silicon substrate by the film, recombination at the interface between the single crystal silicon substrate and the second amorphous film and at the end face of the single crystal silicon substrate is suppressed, and the second amorphous film can be easily reached. Become. And the short circuit photocurrent and the fill factor are improved.

  Therefore, the conversion efficiency of the back contact photoelectric conversion element can be improved.

It is sectional drawing which shows the structure of the photoelectric conversion element by embodiment of this invention. It is a 1st process drawing which shows the manufacturing method of the photoelectric conversion element shown in FIG. It is a 2nd process figure which shows the manufacturing method of the photoelectric conversion element shown in FIG. FIG. 4 is a third process diagram illustrating a method for manufacturing the photoelectric conversion element illustrated in FIG. 1. It is sectional drawing which shows the structure of the other photoelectric conversion element by embodiment of this invention.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  In this specification, the “amorphous phase” refers to a state in which silicon (Si) atoms and the like are randomly arranged. Moreover, although amorphous silicon is described as “a-Si”, this notation actually means that hydrogen (H) atoms are included. Amorphous silicon carbide (a-SiC), amorphous silicon oxide (a-SiO), amorphous silicon nitride (a-SiN), amorphous silicon tin (a-SiSn), amorphous silicon germanium (a-SiGe) and amorphous germanium (a Similarly for -Ge), it means that an H atom is contained.

  FIG. 1 is a cross-sectional view showing a configuration of a photoelectric conversion element according to an embodiment of the present invention. Referring to FIG. 1, a photoelectric conversion element 100 according to an embodiment of the present invention includes an n-type single crystal silicon substrate 1, n-type amorphous films 11 to 1n (n is an integer of 3 or more), i-type Amorphous films 21 to 2n-1, p-type amorphous films 31 to 3n-1, electrodes 41 to 4n, 51 to 5n-1, an oxide film 6, and an antireflection film 7 are provided.

  The n-type single crystal silicon substrate 1 has, for example, a (100) plane orientation and a specific resistance of 0.1 to 1.0 Ω · cm. The n-type single crystal silicon substrate 1 has a thickness of 100 to 300 μm, for example, and preferably has a thickness of 100 to 200 μm.

Each of n-type amorphous films 11, 1 n is provided in contact with the surface opposite to the light incident side of n-type single crystal silicon substrate 1 and the end surface of n-type single crystal silicon substrate 1. Each of n-type amorphous films 12-1n-1 is provided in contact with the surface of n-type single crystal silicon substrate 1 opposite to the light incident side. In this case, the n-type amorphous films 11 to 1 n are arranged at a desired interval in the in-plane direction of the n-type single crystal silicon substrate 1. Each of the n-type amorphous films 11 to 1n is made of, for example, n-type amorphous silicon (n-type a-Si) and has a film thickness of, for example, 10 nm. The phosphorus (P) concentration in each of the n-type amorphous films 11 to 1n is, for example, 5 × 10 ¹⁹ cm ⁻³ .

  The i-type amorphous films 21 to 2n-1 are adjacent to the n-type amorphous films 11 to 1n-1 in the in-plane direction of the n-type single crystal silicon substrate 1, respectively, and the light of the n-type single crystal silicon substrate 1 is used. It is provided in contact with the surface opposite to the incident side. Each of the i-type amorphous films 21 to 2n-1 is made of i-type a-Si and has a film thickness of 10 nm, for example.

The p-type amorphous films 31 to 3n-1 are formed on the i-type amorphous films 21 to 2n-1 in contact with the i-type amorphous films 21 to 2n-1, respectively. Each of the p-type amorphous films 31 to 3n-1 is made of p-type a-Si and has a thickness of 10 nm. Further, the boron (B) concentration in each of the p-type amorphous films 31 to 3n-1 is, for example, 5 × 10 ¹⁹ cm ⁻³ .

  The n-type amorphous films 11 to 1n, the i-type amorphous films 21 to 2n-1 and the p-type amorphous films 31 to 3n-1 have the same length in the direction perpendicular to the paper surface of FIG. The p-type amorphous films 31 to 3n-1 have the same width as the i-type amorphous films 21 to 2n-1 in the in-plane direction of the n-type single crystal silicon substrate 1, respectively. The area occupation ratio, which is the ratio of the total area of the p-type amorphous films 31 to 3n-1 to the area of the n-type single crystal silicon substrate 1, is 60 to 93%. The area occupation ratio, which is the ratio of the entire area of 11 to 1n to the area of the n-type single crystal silicon substrate 1, is 5 to 20%.

  As described above, the area occupation ratio of the p-type amorphous films 31 to 3n-1 is larger than the area occupation ratio of the n-type amorphous films 11 to 1n in the n-type single crystal silicon substrate 1. Electrons and holes are easily separated by pin junctions (p-type amorphous films 31 to 3n-1 / i-type amorphous films 21 to 2n-1 / n-type single crystal silicon substrate 1) and photoexcited. This is to increase the contribution ratio of electrons and holes to power generation.

  The electrodes 41 to 4n are formed on the n-type amorphous films 11 to 1n in contact with the n-type amorphous films 11 to 1n, respectively. The electrodes 51-5n-1 are formed on the p-type amorphous films 31-3n-1 in contact with the p-type amorphous films 31-3n-1, respectively. And each of the electrodes 41-4n and 51-5n-1 consists of silver (Ag), for example.

Oxide film 6 is formed on n-type single crystal silicon substrate 1 in contact with the light incident surface of n-type single crystal silicon substrate 1. The oxide film 6 is made of silicon dioxide (SiO _2), the film thickness is, for example, 10 to 100 nm.

The antireflection film 7 is formed on the oxide film 6 in contact with the oxide film 6. The antireflection film 7 is made of, for example, silicon nitride (Si ₃ N ₄ ), and the film thickness is, for example, 10 to 100 nm.

  2-4 is a 1st-3rd process drawing which respectively shows the manufacturing method of the photoelectric conversion element 100 shown in FIG.

  A method for manufacturing the photoelectric conversion element 100 will be described. The photoelectric conversion element 100 is manufactured by a plasma CVD method mainly using a plasma apparatus.

  The plasma apparatus includes a preparation chamber, reaction chambers CB1 to CB3, an extraction chamber, a matching unit, and an RF power source. The charging chamber, the reaction chambers CB1 to CB3, and the take-out chamber are linearly arranged. A partition valve is used to partition between the charging chamber and the reaction chamber CB1, between the reaction chamber CB1 and the reaction chamber CB2, between the reaction chamber CB2 and the reaction chamber CB3, and between the reaction chamber CB3 and the take-out chamber. It has been. Further, the plasma apparatus is provided with a transport mechanism for sequentially transporting the single crystal silicon substrate from the preparation chamber to the reaction chamber CB1, the reaction chamber CB2, the reaction chamber CB3, and the take-out chamber.

The charging chamber includes a heating mechanism and an exhaust mechanism. The heating mechanism raises the temperature of the single crystal silicon substrate to a predetermined temperature. The exhaust mechanism exhausts the gas in the preparation chamber, and sets the ultimate pressure in the preparation chamber to, for example, 1 × 10 ⁻⁵ Pa or less.

Each of the reaction chambers CB1 to CB3 includes a parallel plate electrode, a heating mechanism, and an exhaust mechanism. The heating mechanism raises the temperature of the single crystal silicon substrate to a predetermined temperature. The exhaust mechanism exhausts the gases in the reaction chambers CB1 to CB3, and sets the ultimate pressure in the reaction chambers CB1 to CB3 to, for example, 1 × 10 ⁻⁵ Pa or less. The parallel plate electrodes are connected to an RF power source through a matching unit.

The take-out chamber includes an exhaust mechanism. The exhaust mechanism exhausts the gas in the extraction chamber and sets the ultimate pressure in the extraction chamber to, for example, 1 × 10 ⁻⁵ Pa or less.

  Each exhaust mechanism of the charging chamber, the reaction chambers CB1 to CB3, and the take-out chamber includes a turbo molecular pump, a mechanical booster pump, and a rotary pump. The turbo molecular pump, the mechanical booster pump and the rotary pump are serially connected to the charging chamber, the reaction chambers CB1 to CB3 and the extraction chamber, respectively, so that the turbo molecular pump is closest to the charging chamber, the reaction chambers CB1 to CB3 and the extraction chamber. It is connected to. Each exhaust mechanism exhausts the gas in the charging chamber, reaction chambers CB1 to CB3, and the extraction chamber with a turbo molecular pump, a mechanical booster pump, and a rotary pump, respectively, or is charged with a mechanical booster pump and a rotary pump, respectively. The gases in the chamber, reaction chambers CB1 to CB3 and the extraction chamber are exhausted.

  The RF power source applies, for example, RF power of 13.56 MHz to the parallel plate electrodes of the reaction chambers CB1 to CB3 via the matching unit.

  When the manufacture of the photoelectric conversion element 100 is started, the n-type single crystal silicon substrate 1 is ultrasonically cleaned with ethanol or the like and degreased, and then the n-type single crystal silicon substrate 1 is immersed in hydrofluoric acid to be n-type. The natural oxide film formed on the surface of the single crystal silicon substrate 1 is removed, and the surface of the n-type single crystal silicon substrate 1 is terminated with hydrogen (see step (a) in FIG. 2).

  When the cleaning of the n-type single crystal silicon substrate 1 is completed, the n-type single crystal silicon substrate 1 is put into an oxidation furnace, and the surface of the n-type single crystal silicon substrate 1 is thermally oxidized at a temperature of 975 ° C. for 10 minutes in an oxygen atmosphere, for example. An oxide film 6 is formed on the surface of the crystalline silicon substrate 1 (see step (b) in FIG. 2).

Thereafter, the oxide film 6 / n-type single crystal silicon substrate 1 is put into a sputtering apparatus, and an antireflection film 7 (= Si ₃ N ₄ ) is formed on the oxide film 6 by sputtering (see step (c) in FIG. 2). .

  After the formation of the antireflection film 7, the oxide film formed on the surface of the n-type single crystal silicon substrate 1 opposite to the surface on which the antireflection film 7 is formed and the end surface of the n-type single crystal silicon substrate 1 are formed with hydrofluoric acid. While removing, the end surface and surface of the n-type single crystal silicon substrate 1 are terminated with hydrogen.

  When the end face and the surface of the n-type single crystal silicon substrate 1 are terminated with hydrogen, the n-type single crystal silicon substrate 1 / oxide film 6 / antireflection film 7 are arranged on the substrate holder in the preparation chamber of the plasma apparatus.

And the exhaust mechanism of the preparation chamber exhausts the gas in the preparation chamber to 1 × 10 ⁻⁵ Pa or less, and the heating mechanism of the preparation chamber is the temperature of the n-type single crystal silicon substrate 1 / oxide film 6 / antireflection film 7. The substrate holder is heated so that is set to 200 ° C. Further, the heating mechanism of the reaction chambers CB1 to CB3 also heats the substrate holder so that the temperature of the n-type single crystal silicon substrate 1 and the like is set to 200 ° C.

  When the temperature of the n-type single crystal silicon substrate 1 / oxide film 6 / antireflection film 7 reaches 200 ° C., the partition valve between the preparation chamber and the reaction chamber CB1 is opened, and the n-type single crystal silicon substrate 1 / oxidation is made. The film 6 / antireflection film 7 is transferred from the preparation chamber to the reaction chamber CB1.

  Table 1 shows the flow rate of the material gas when forming the n-type amorphous films 11 to 1n, the i-type amorphous films 21 to 2n-1 and the p-type amorphous films 31 to 3n-1.

When the n-type single crystal silicon substrate 1 / oxide film 6 / antireflection film 7 was transferred to the reaction chamber CB1, it was diluted with 20 sccm of silane (SiH ₄ ) gas, 150 sccm of hydrogen (H ₂ ) gas, and hydrogen. 50 sccm of phosphine (PH ₃ ) gas is allowed to flow into the reaction chamber CB1, and the pressure in the reaction chamber CB1 is set in the range of 6.5 Pa to 330 Pa. The RF power source applies RF power in the range of 8 to 40 mW / cm ² to the parallel plate electrodes via the matching unit. As a result, plasma is generated in the reaction chamber CB1, and an n-type amorphous film 10 made of n-type a-Si is deposited on the surface and end face of the n-type single crystal silicon substrate 1 (step (d) in FIG. )reference). The concentration of PH ₃ gas diluted with hydrogen is 0.2%.

In the n-type amorphous film 10 made of n-type a-Si, the dilution rate of SiH ₄ gas by H ₂ gas is set as high as possible in the range where n-type a-Si does not crystallize, and the n-type single crystal silicon substrate As compared with the case where n-type a-Si is formed only on the surface of 1, the reaction pressure and the RF power are lowered, and the migration of active species on the n-type single crystal silicon substrate 1 contributing to the deposition of n-type a-Si is performed. Secured and formed. Thereby, n-type amorphous film 10 is formed on the surface and end face of n-type single crystal silicon substrate 1.

When the thickness of the n-type amorphous film 10 reaches 10 nm, the application of RF power to the parallel plate electrodes in the reaction chamber CB1 is stopped, and SiH ₄ gas, H ₂ gas, and PH ₃ gas are supplied to the reaction chamber CB1. The supply is stopped, and the reaction chamber CB1 is evacuated to 1 × 10 ⁻⁵ Pa or less by an exhaust mechanism. Then, the gate valve is opened, and the n-type amorphous film 10 / n-type single crystal silicon substrate 1 / oxide film 6 / antireflection film 7 is transferred from the reaction chamber CB1 to the take-out chamber, and the n-type amorphous film 10 / The n-type single crystal silicon substrate 1 / oxide film 6 / antireflection film 7 is cooled to room temperature and then taken out.

  Thereafter, a resist is applied to the surface and end face of the n-type amorphous film 10 by spin coating, and the applied resist is patterned by photolithography to form a resist pattern 20 (see step (e) in FIG. 2). .

  Then, a part of the n-type amorphous film 10 is etched by dry etching using the resist pattern 20 as a mask. As a result, n-type amorphous films 11 to 1n are formed (see step (f) in FIG. 3).

  Subsequently, a resist is applied to the surfaces and end faces of the n-type amorphous films 11 to 1n and the surface of the n-type single crystal silicon substrate 1 by spin coating, and the applied resist is patterned by photolithography to form a resist pattern 30. (See step (g) in FIG. 3).

Then, the resist pattern 30 / n-type amorphous film 11 to 1n / n-type single crystal silicon substrate 1 / oxide film 6 / antireflection film 7 are put in a plasma apparatus charging chamber, and the charging chamber is set to 1 × 10 ⁻⁵ Pa. While exhausting below, the resist pattern 30 / n-type amorphous film 11 to 1n / n-type single crystal silicon substrate 1 / oxide film 6 / antireflection film 7 are heated to 200 ° C.

  Then, resist pattern 30 / n-type amorphous film 11 to 1n / n-type single crystal silicon substrate 1 / oxide film 6 / antireflection film 7 are transferred from the preparation chamber to reaction chamber CB2.

When the resist pattern 30 / n-type amorphous film 11 to 1n / n-type single crystal silicon substrate 1 / oxide film 6 / antireflection film 7 is transferred to the reaction chamber CB2, 10 sccm of SiH ₄ gas and 100 sccm of H _Two gases are allowed to flow into the reaction chamber CB2 (see Table 1), and the pressure in the reaction chamber CB2 is set in the range of 13.3 Pa to 665 Pa. The RF power source applies RF power in the range of 16 to 80 mW / cm ² to the parallel plate electrodes through the matching unit. As a result, plasma is generated in the reaction chamber CB2, i-type amorphous films 21 to 2n-1 made of i-type a-Si are deposited on the surface of the n-type single crystal silicon substrate 1, and i-type a An i-type amorphous film 40 made of -Si is deposited on the resist pattern 30 (see step (h) in FIG. 3).

When the film thickness of the i-type amorphous films 21 to 2n-1 and 40 reaches 10 nm, the application of RF power to the parallel plate electrodes in the reaction chamber CB2 is stopped and the reaction chamber CB2 of SiH ₄ gas and H ₂ gas is used. The reaction chamber CB2 is evacuated to 1 × 10 ⁻⁵ Pa or less by an exhaust mechanism. Then, the gate valve is opened, i-type amorphous films 21 to 2n-1, 40 / resist pattern 30 / n-type amorphous films 11 to 1n / n-type single crystal silicon substrate 1 / oxide film 6 / antireflection film 7 is transferred from the reaction chamber CB2 to the reaction chamber CB3.

i-type amorphous films 21 to 2n-1, 40 / resist pattern 30 / n-type amorphous films 11 to 1n / n-type single crystal silicon substrate 1 / oxide film 6 / antireflection film 7 are transferred to reaction chamber CB3. Then, 2 sccm of SiH ₄ gas, 42 sccm of H ₂ gas, and 12 sccm of diborane (B ₂ H ₆ ) gas diluted with hydrogen flow into the reaction chamber CB3 (see Table 1), and the pressure in the reaction chamber CB3 Is set in the range of 13.3 Pa to 665 Pa. The RF power source applies RF power in the range of 16 to 80 mW / cm ² to the parallel plate electrodes through the matching unit. As a result, plasma is generated in the reaction chamber CB3, and p-type amorphous films 31 to 3n-1 made of p-type a-Si are deposited on the i-type amorphous films 21 to 2n-1, respectively. Then, a p-type amorphous film 50 made of p-type a-Si is deposited on the i-type amorphous film 40 (see step (i) in FIG. 3). The concentration of hydrogen diluted B ₂ H ₆ gas is, for example, 0.1%.

When the thickness of the p-type amorphous films 31 to 3n-1 and 50 reaches 10 nm, the application of RF power to the parallel plate electrodes in the reaction chamber CB3 is stopped, and SiH ₄ gas, H ₂ gas, and B ₂ H are stopped. The supply of ₆ gases to the reaction chamber CB3 is stopped, and the reaction chamber CB3 is evacuated to 1 × 10 ⁻⁵ Pa or less by an exhaust mechanism. Then, the gate valve is opened, and the p-type amorphous films 31 to 3n-1, 50 / i-type amorphous films 21 to 2n-1, 40 / resist pattern 30 / n-type amorphous films 11 to 1n / n. Type single crystal silicon substrate 1 / oxide film 6 / antireflection film 7 is transferred from reaction chamber CB3 to the take-out chamber, and p-type amorphous films 31-3n-1, 50 / i-type amorphous films 21-2n- 1,40 / resist pattern 30 / n-type amorphous film 11 to 1n / n-type single crystal silicon substrate 1 / oxide film 6 / antireflection film 7 are cooled to room temperature.

  p-type amorphous films 31 to 3n-1, 50 / i-type amorphous films 21 to 2n-1, 40 / resist pattern 30 / n-type amorphous films 11 to 1n / n-type single crystal silicon substrate 1 / When the oxide film 6 / antireflection film 7 is cooled to room temperature, the p-type amorphous films 31-3n-1, 50 / i-type amorphous films 21-2n-1, 40 / resist pattern 30 / n-type The amorphous films 11 to 1n / n type single crystal silicon substrate 1 / oxide film 6 / antireflection film 7 are taken out from the extraction chamber, and the p type amorphous films 31 to 3n-1, 50 / i type amorphous film are taken out. The resist pattern 30 of 21-2n-1, 40 / resist pattern 30 / n-type amorphous film 11-1n / n-type single crystal silicon substrate 1 / oxide film 6 / antireflection film 7 is removed.

  Thereby, the i-type amorphous film 40 and the p-type amorphous film 50 are removed by lift-off, and the n-type amorphous films 11 and 12 are formed in contact with the surface and end face of the n-type single crystal silicon substrate 1. , N-type amorphous films 12-1n-1 and i-type amorphous films 21-2n-1 are formed in contact with the surface of n-type single crystal silicon substrate 1, and p-type amorphous films 31-3n- 1 are formed on the i-type amorphous films 21 to 2n−1, respectively (see step (j) in FIG. 4).

  Thereafter, a resist is applied to the n-type amorphous films 11 to 1n and the p-type amorphous films 31 to 3n-1 by spin coating, and the applied resist is patterned by photolithography to form a resist pattern 60. (See step (k) in FIG. 4).

  Then, Ag is formed on the n-type amorphous films 11 to 1n and the p-type amorphous films 31 to 3n-1 by vapor deposition or sputtering using the resist pattern 60 as a mask, and the resist pattern 60 is removed. Thus, the electrodes 41 to 4n and the electrodes 51 to 5n-1 are formed on the n-type amorphous films 11 to 1n and the p-type amorphous films 31 to 3n-1, respectively, and the photoelectric conversion element 100 is completed ( Step (l) in FIG. 4).

  When sunlight is applied to the photoelectric conversion element 100 from the antireflection film 7 side, the antireflection film 7 reduces the reflection of sunlight and guides the sunlight into the n-type single crystal silicon substrate 1. Then, electrons and holes are photoexcited in the n-type single crystal silicon substrate 1.

  Even if the photoexcited electrons and holes reach the interface between the n-type single crystal silicon substrate 1 and the oxide film 6, they are difficult to recombine at the interface between the n-type single crystal silicon substrate 1 and the oxide film 6, and the n-type It diffuses toward the amorphous films 11-1n and i-type amorphous films 21-2n-1. Thus, the oxide film 6 suppresses recombination of photoexcited electrons and holes on the light incident side surface of the n-type single crystal silicon substrate 1.

  Then, the photoexcited electrons and holes are diffused to the n-type amorphous films 11 to 1n and i-type amorphous films 21 to 2n-1 side, and p-type amorphous films 31 to 3n-1 / i. Type amorphous films 21 to 2n-1 / n type single crystal silicon substrate 1 (= pin junction) are separated by an internal electric field, and holes are separated from i type amorphous films 21 to 2n-1 and p type amorphous. The electrons reach the electrodes 51 to 5n-1 via the material films 31 to 3n-1, and the electrons reach the electrodes 41 to 4n via the n-type amorphous films 11 to 1n.

  The electrons that have reached the electrodes 41 to 4n reach the electrodes 51 to 5n-1 via a load connected between the electrodes 41 to 4n and the electrodes 51 to 5n-1, and recombine with the holes.

  Thus, in the photoelectric conversion element 100, the back surface of the n-type single crystal silicon substrate 1 (= the oxide film 6 and the antireflection film 7 is formed). This is a back contact type photoelectric conversion element taken out from the surface opposite to the surface of the n-type single crystal silicon substrate 1.

  As described above, in the photoelectric conversion element 100, the end surface of the n-type single crystal silicon substrate 1 is covered with the n-type amorphous films 11 and 1n (= n-type a-Si), and the n-type single crystal silicon substrate is covered. 1 (the surface opposite to the surface on which the oxide film 6 is formed) are n-type amorphous films 11 to 1n (= n-type a-Si) and i-type amorphous films 21 to 2n-1 ( = I-type a-Si).

  As a result, the holes photoexcited in the n-type single crystal silicon substrate 1 are caused by the passivation effect of the n-type single crystal silicon substrate 1 by the i-type amorphous films 21 to 2n-1 (= i-type a-Si). It becomes difficult to recombine at the interface between the n-type single crystal silicon substrate 1 and the i-type amorphous films 21 to 2n-1, and the i-type amorphous films 21 to 2n-1 and the p-type amorphous films 31 to 3n. It becomes easy to reach the electrodes 51 to 5n-1 through -1.

  The electrons photoexcited in the n-type single crystal silicon substrate 1 are converted into n-type single crystal by the passivation effect of the n-type single crystal silicon substrate 1 by the n-type amorphous films 11 to 1n (= n-type a-Si). It becomes difficult to recombine at the end face and the surface of the silicon substrate 1, and it is easy to reach the electrodes 41 to 4n via the n-type amorphous films 11 to 1n. In particular, since no i-type amorphous film is inserted between the n-type single crystal silicon substrate 1 and the n-type amorphous films 11 to 1n, the series resistance to photoexcited electrons is reduced, and photoexcitation is performed. Compared with the case where the i-type amorphous film is inserted between the n-type single crystal silicon substrate 1 and the n-type amorphous films 11 to 1n, the n-type amorphous films 11 to 1n It becomes easy to reach the electrodes 41 to 4n via the.

  Therefore, the short circuit photocurrent Isc and the fill factor FF are improved, and the conversion efficiency of the photoelectric conversion element 100 can be improved.

  In the photoelectric conversion element 100, the n-type amorphous films 11 and 1n are disposed at both ends in the in-plane direction of the n-type single crystal silicon substrate 1. The conductivity type of the n-type amorphous films 11 and 1n is the same as that of the n-type single crystal silicon substrate 1. The optical band gap of the n-type amorphous films 11 and 1n (= n-type a-Si) is about 1.7 eV, and the optical band gap of the n-type single crystal silicon substrate 1 is about 1.1 eV. is there. Further, the activation energy of the n-type amorphous films 11 and 1n (= n-type a-Si) is about 0.2 eV, and the activation energy of the n-type single crystal silicon substrate 1 is 0.14 to 0. 19 eV. Therefore, the junction between the n-type single crystal silicon substrate 1 and the n-type amorphous film 11, 1n forms a heterojunction, and the conduction band edge of the n-type amorphous film 11, 1n is n-type single crystal silicon. The energy is lower than the conduction band edge of the substrate 1, and the valence band edges of the n-type amorphous films 11 and 1 n are higher in energy than the valence band edge of the n-type single crystal silicon substrate 1.

  As a result, an electric field for holes exists at the interface between the n-type single crystal silicon substrate 1 / n-type amorphous film 11 and 1n, and the photoexcited holes (minority carriers) are transferred to the n-type single crystal silicon substrate 1 / n. The inner circumference in the in-plane direction of the n-type single crystal silicon substrate 1 due to the electric field present at the interface between the single crystal silicon substrate 1 / n-type amorphous film 11 and 1n even if it diffuses near the interface between the n-type amorphous film 11 and 1n It becomes easy to reach the p-type amorphous films 31 to 3n−1.

  That is, by disposing the n-type amorphous films 11 and 1n at both ends in the in-plane direction of the n-type single crystal silicon substrate 1, holes which are minority carriers in the photoelectric conversion element 100 are converted into p-type amorphous films. It becomes easy to reach 31 to 3n-1, and the conversion efficiency of the photoelectric conversion element 100 can be improved.

  Therefore, in the photoelectric conversion element 100, the n-type amorphous films 11 and 1n having the same conductivity type as the n-type single crystal silicon substrate 1 are disposed at both ends of the n-type single crystal silicon substrate 1. .

  FIG. 5 is a sectional view showing a configuration of another photoelectric conversion element according to the embodiment of the present invention. The photoelectric conversion element according to the embodiment of the present invention may be a photoelectric conversion element 200 shown in FIG.

  Referring to FIG. 5, photoelectric conversion element 200 includes a p-type single crystal silicon substrate 101, p-type amorphous films 111 to 11 n, i-type amorphous films 121 to 12 n −1, and an n-type amorphous film. A material film 131 to 13-1, electrodes 141 to 14n, 151 to 15n-1, an oxide film 6, and an antireflection film 7 are provided.

  The p-type single crystal silicon substrate 101 has, for example, a (100) plane orientation and a specific resistance of 0.1 to 1.0 Ω · cm. The p-type single crystal silicon substrate 101 has a thickness of 100 to 300 μm, for example, and preferably has a thickness of 100 to 200 μm.

Each of p-type amorphous films 111 and 11n is provided in contact with the surface opposite to the light incident side of p-type single crystal silicon substrate 101 and the end surface of p-type single crystal silicon substrate 101. Each of the p-type amorphous films 112 to 11n-1 is provided in contact with the surface of the p-type single crystal silicon substrate 101 opposite to the light incident side. In this case, the p-type amorphous films 111 to 11n are arranged at a desired interval in the in-plane direction of the p-type single crystal silicon substrate 101. Each of the p-type amorphous films 111 to 11n is made of, for example, p-type a-Si, and has a film thickness of, for example, 10 nm. The B concentration in each of the p-type amorphous films 111 to 11n is, for example, 5 × 10 ¹⁹ cm ⁻³ .

  The i-type amorphous films 121 to 12n-1 are adjacent to the p-type amorphous films 111 to 11n-1 in the in-plane direction of the p-type single crystal silicon substrate 101, respectively. It is provided in contact with the surface opposite to the incident side. Each of the i-type amorphous films 121 to 12n-1 is made of i-type a-Si and has a film thickness of, for example, 10 nm.

The n-type amorphous films 131 to 13n-1 are formed on the i-type amorphous films 121 to 12n-1 in contact with the i-type amorphous films 121 to 12n-1, respectively. Each of the n-type amorphous films 131 to 13n-1 is made of n-type a-Si and has a thickness of 10 nm. Further, the P concentration in each of the n-type amorphous films 131 to 13n−1 is, for example, 5 × 10 ¹⁹ cm ⁻³ .

  The electrodes 141 to 14n are formed on the p-type amorphous films 111 to 11n in contact with the p-type amorphous films 111 to 11n, respectively. The electrodes 151 to 15n-1 are formed on the n-type amorphous films 131 to 13n-1 in contact with the n-type amorphous films 131 to 13n-1, respectively. Each of the electrodes 141 to 14n and 151 to 15n-1 is made of Ag, for example.

  The p-type amorphous films 111 to 11n, the i-type amorphous films 121 to 12n-1 and the n-type amorphous films 131 to 13n-1 have the same length in the direction perpendicular to the paper surface of FIG. The n-type amorphous films 131 to 13n-1 have the same width as that of the i-type amorphous films 121 to 12n-1 in the in-plane direction of the p-type single crystal silicon substrate 101, respectively. The area occupation ratio, which is the ratio of the entire area of the n-type amorphous films 131 to 13n-1 to the area of the p-type single crystal silicon substrate 101, is 60 to 93%. The area occupation ratio, which is the ratio of the entire area of 111 to 11n to the area of the p-type single crystal silicon substrate 101, is 5 to 20%.

  As described above, the area occupation ratio of the n-type amorphous films 131 to 13n-1 is made larger than the area occupation ratio of the p-type amorphous films 111 to 11n by photoexcitation in the p-type single crystal silicon substrate 101. Electrons and holes are easily separated by pin junctions (n-type amorphous films 131 to 13n-1 / i-type amorphous films 121 to 12n-1 / p-type single crystal silicon substrate 101) and photoexcited. This is to increase the contribution ratio of electrons and holes to power generation.

  The oxide film 6 is made of the above-described material and is formed on the p-type single crystal silicon substrate 101 in contact with the light incident side surface of the p-type single crystal silicon substrate 101. The film thickness of the oxide film 6 is as described above.

  The antireflection film 7 is made of the above-described material, and is formed on the oxide film 6 in contact with the oxide film 6. The film thickness of the antireflection film 7 is as described above.

  The photoelectric conversion element 200 is manufactured according to the same steps as the steps (a) to (l) shown in FIGS.

  In this case, in the step (d), the p-type amorphous films (= p-type a-Si) for the p-type amorphous films 111 to 11n use the gas flow rate shown in Table 1, the reaction pressure described above, and the like. It is formed in contact with the surface and end face of p-type single crystal silicon substrate 101 by plasma CVD. Then, in steps (e) and (f), the p-type amorphous films 111 and 11n are formed in contact with the surface and the end face of the p-type single crystal silicon substrate 101, and the p-type amorphous films 112 to 11n−1. Is formed in contact with the surface of the p-type single crystal silicon substrate 101.

  In steps (g) and (h), the i-type amorphous films 121 to 12n-1 (= i-type a-Si) are p-type single crystal silicon by plasma CVD using the gas flow rate shown in Table 1. In the step (i), the n-type amorphous films 131 to 13n-1 (= n-type a-Si) are formed by plasma CVD using the gas flow rates shown in Table 1, respectively. It is formed in contact with i-type amorphous films 121 to 12n-1.

  Further, in steps (k) and (l), the electrodes 141 to 14n and the electrodes 151 to 15n-1 are formed in contact with the p-type amorphous films 111 to 11n and the n-type amorphous films 131 to 13n-1, respectively. Is done.

  When sunlight is applied to the photoelectric conversion element 200 from the antireflection film 7 side, the antireflection film 7 reduces the reflection of sunlight and guides the sunlight into the p-type single crystal silicon substrate 101. Then, electrons and holes are photoexcited in the p-type single crystal silicon substrate 101.

  The photoexcited electrons and holes are difficult to recombine at the interface between the p-type single crystal silicon substrate 101 and the oxide film 6 even when they reach the interface between the p-type single crystal silicon substrate 101 and the oxide film 6, and are thus p-type. It diffuses toward the amorphous films 111 to 11n and the i-type amorphous films 121 to 12n-1. Thus, the oxide film 6 suppresses recombination of photoexcited electrons and holes on the light incident side surface of the p-type single crystal silicon substrate 101.

  Then, the photoexcited electrons and holes are diffused toward the p-type amorphous films 111 to 11n and the i-type amorphous films 121 to 12n-1 to form the p-type single crystal silicon substrate 101 / i-type amorphous. Films 121 to 12n-1 / p-type amorphous films 131 to 13n-1 are separated by an internal electric field, and electrons are separated from i-type amorphous films 121 to 12n-1 and n-type amorphous films 131 to 13n- 1 reaches the electrodes 151 to 15n−1, and the holes reach the electrodes 141 to 14n via the p-type amorphous films 111 to 11n.

  The electrons that have reached the electrodes 141 to 14n reach the electrodes 151 to 15n-1 via a load connected between the electrodes 141 to 14n and the electrodes 151 to 15n-1, and recombine with the holes.

  Thus, in the photoelectric conversion element 200, electrons and holes photoexcited in the p-type single crystal silicon substrate 101 are converted into the back surface of the p-type single crystal silicon substrate 101 (= the oxide film 6 and the antireflection film 7 are formed). This is a back contact photoelectric conversion element that is taken out from the surface opposite to the surface of the p-type single crystal silicon substrate 101.

  In the photoelectric conversion element 200, the end surface of the p-type single crystal silicon substrate 101 is covered with the p-type amorphous films 111 and 11n (= p-type a-Si), and the back surface of the p-type single crystal silicon substrate 101 (oxidation). The surface opposite to the surface on which the film 6 is formed is a p-type amorphous film 111 to 11n (= p-type a-Si) and an i-type amorphous film 121 to 12n-1 (= i-type a- Covered with Si).

  As a result, the electrons photoexcited in the p-type single crystal silicon substrate 101 are converted into p by the passivation effect of the p-type single crystal silicon substrate 101 by the i-type amorphous films 121 to 12n-1 (= i-type a-Si). Recombination becomes difficult at the interface between the p-type single crystal silicon substrate 101 and the i-type amorphous films 121 to 12n-1, and the i-type amorphous films 121 to 12n-1 and the n-type amorphous films 131 to 13n- 1 to reach the electrodes 151 to 15n-1.

  Further, the holes photoexcited in the p-type single crystal silicon substrate 101 are converted into p-type single crystals by the passivation effect of the p-type single crystal silicon substrate 101 by the p-type amorphous films 111 to 11n (= p-type a-Si). It becomes difficult to recombine at the end face and the surface of the crystalline silicon substrate 101, and it is easy to reach the electrodes 141 to 14n via the p-type amorphous films 111 to 11n. In particular, since no i-type amorphous film is inserted between the p-type single crystal silicon substrate 101 and the p-type amorphous films 111 to 11n, the series resistance to photoexcited holes is reduced, The photoexcited holes are generated in the p-type amorphous film 111 as compared with the case where the i-type amorphous film is inserted between the p-type single crystal silicon substrate 101 and the p-type amorphous films 111 to 11n. It becomes easy to reach the electrodes 141 to 14n through ˜11n.

  Therefore, the short circuit photocurrent Isc and the fill factor FF are improved, and the conversion efficiency of the photoelectric conversion element 200 can be improved.

  In the photoelectric conversion element 200, the p-type amorphous films 111 and 11n are disposed at both ends in the in-plane direction of the p-type single crystal silicon substrate 101. The conductivity type of the p-type amorphous films 111 and 11n is the same as that of the p-type single crystal silicon substrate 101. The optical band gap of the p-type amorphous films 111 and 11n (= p-type a-Si) is about 1.7 eV, and the optical band gap of the p-type single crystal silicon substrate 101 is about 1.1 eV. is there. Further, the activation energy of the p-type amorphous films 111 and 11n (= p-type a-Si) is about 0.3 eV, and the activation energy of the p-type single crystal silicon substrate 101 is 0.14 to 0. 19 eV. Therefore, the junction between the p-type single crystal silicon substrate 101 and the p-type amorphous films 111 and 11n constitutes a heterojunction, and the conduction band edges of the p-type amorphous films 111 and 11n are p-type single crystal silicon. The valence band edge of the p-type amorphous films 111 and 11n is lower in energy than the valence band edge of the p-type single crystal silicon substrate 101.

  As a result, an electric field for electrons exists at the interface between the p-type single crystal silicon substrate 101 / p-type amorphous films 111 and 11n, and photoexcited electrons (minority carriers) are converted into p-type single crystal silicon substrate 101 / p-type non-crystal. The inner circumference in the in-plane direction of the p-type single crystal silicon substrate 101 due to the electric field existing at the interface between the p-type single crystal silicon substrate 101 / p-type amorphous film 111 and 11n even if it diffuses near the crystalline film 111, 11n interface. It becomes easy to reach the n-type amorphous films 131 to 13n−1.

  That is, by disposing the p-type amorphous films 111 and 11n at both ends in the in-plane direction of the p-type single crystal silicon substrate 101, electrons which are minority carriers in the photoelectric conversion element 200 are converted into the n-type amorphous film 131. It becomes easy to reach ˜13n−1, and the conversion efficiency of the photoelectric conversion element 200 can be improved.

  Therefore, also in the photoelectric conversion element 200, the p-type amorphous films 111 and 11n having the same conductivity type as the p-type single crystal silicon substrate 101 are arranged at both ends of the p-type single crystal silicon substrate 101. .

  In the photoelectric conversion element 100, the surface on the light incident side of the n-type single crystal silicon substrate 1 (= the surface on which the oxide film 6 is formed) may have a texture structure. In this case, in the step (a) of FIG. 2, after the n-type single crystal silicon substrate 1 is ultrasonically cleaned with ethanol or the like, the surface of the n-type single crystal silicon substrate 1 is chemically anisotropically etched using alkali. Then, the surface of the n-type single crystal silicon substrate 1 is textured. Thereafter, as described above, the natural oxide film is removed using hydrofluoric acid, and the surface of the n-type single crystal silicon substrate 1 is terminated with hydrogen.

  The same applies to the photoelectric conversion element 200 in which the surface on the light incident side of the p-type single crystal silicon substrate 101 (= the surface on which the oxide film 6 is formed) has a texture structure.

  Further, in the photoelectric conversion element 100, the n-type amorphous films 11 to 1n have been described as being made of n-type a-Si. However, the embodiment of the present invention is not limited to this, and the n-type amorphous film is not limited thereto. The films 11 to 1n are n-type amorphous silicon carbide (n-type a-SiC), n-type amorphous silicon oxide (n-type a-SiO), n-type amorphous silicon nitride (n-type a-SiN), n-type amorphous silicon. It may consist of any of tin (n-type a-SiSn), n-type amorphous silicon germanium (n-type a-SiGe), and n-type amorphous germanium (n-type a-Ge).

  Furthermore, in the photoelectric conversion element 100, the i-type amorphous films 21 to 2n-1 have been described as being made of i-type a-Si. However, in the embodiment of the present invention, the i-type non-film is not limited thereto. The crystalline films 21 to 2n-1 may be made of any of i-type a-SiC, i-type a-SiO, i-type a-SiN, i-type a-SiSn, and i-type a-SiGe.

  Furthermore, in the photoelectric conversion element 100, it has been described that the p-type amorphous films 31 to 3n-1 are made of p-type a-Si. The crystalline films 31 to 3n-1 are made of any one of p-type a-SiC, p-type a-SiO, p-type a-SiN, p-type a-SiSn, p-type a-SiGe, and p-type a-Ge. It may be.

  That is, in the photoelectric conversion element 100, the n-type amorphous films 11 to 1n, the i-type amorphous films 21 to 2n-1 and the p-type amorphous films 31 to 3n-1 are shown in Table 2, respectively. It may consist of any of the materials.

In this case, n-type a-SiC is formed by the above-described plasma CVD method using SiH ₄ gas, methane (CH ₄ ) gas, PH ₃ gas, and H ₂ gas as material gases. The n-type a-SiO is formed by the above-described plasma CVD method using SiH ₄ gas, oxygen (O ₂ ) gas, PH ₃ gas, and H ₂ gas as material gases. The n-type a-SiN is formed by the above-described plasma CVD method using SiH ₄ gas, ammonia (NH ₃ ) gas, PH ₃ gas, and H ₂ gas as material gases. n-type a-SiSn is formed by the above-described plasma CVD method using SiH ₄ gas, tin tetrachloride (SnCl ₄ ) gas, PH ₃ gas, and H ₂ gas as material gases. The n-type a-SiGe is formed by the above-described plasma CVD method using SiH ₄ gas, germane (GeH ₄ ) gas, PH ₃ gas, and H ₂ gas as material gases. The n-type a-Ge is formed by the above-described plasma CVD method using GeH ₄ gas, PH ₃ gas, and H ₂ gas as material gases.

Further, i-type a-SiC is formed by the above-described plasma CVD method using SiH ₄ gas, CH ₄ gas, and H ₂ gas as material gases. i-type a-SiO is formed by the above-described plasma CVD method using SiH ₄ gas, O ₂ gas, and H ₂ gas as material gases. i-type a-SiN is formed by the above-described plasma CVD method using SiH ₄ gas, NH ₃ gas, and H ₂ gas as material gases. i-type a-SiSn is formed by the above-described plasma CVD method using SiH ₄ gas, SnCl ₄ gas, and H ₂ gas as material gases. i-type a-SiGe is formed by the above-described plasma CVD method using SiH ₄ gas, GeH ₄ gas, and H ₂ gas as material gases.

  Note that i-type a-Ge is also assumed as the i-type amorphous films 21 to 2n-1, but i-type a-Ge has an optical band gap smaller than that of the n-type single crystal silicon substrate 1, When i-type a-Ge is used as the i-type amorphous films 21 to 2n-1, it is difficult to improve the open circuit voltage Voc. This is because in the photoelectric conversion element 100, the optical band gap of the i-type amorphous films 21 to 2n-1 dominantly determines the open circuit voltage Voc.

  Therefore, in the embodiment of the present invention, i-type a-SiC, i-type a-SiN, i-type a-SiN, i-type a-Si, i, which are larger than the optical band gap of the n-type single crystal silicon substrate 1. The type a-SiSn and i-type a-SiGe were used as the i-type amorphous films 21 to 2n-1.

Further, p-type a-SiC is formed by the above-described plasma CVD method using SiH ₄ gas, CH ₄ gas, B ₂ H ₆ gas and H ₂ gas as material gases. The p-type a-SiO is formed by the above-described plasma CVD method using SiH ₄ gas, O ₂ gas, B ₂ H ₆ gas, and H ₂ gas as material gases. The p-type a-SiN is formed by the above-described plasma CVD method using SiH ₄ gas, NH ₃ gas, B ₂ H ₆ gas and H ₂ gas as material gases. The p-type a-SiSn is formed by the above-described plasma CVD method using SiH ₄ gas, SnCl ₄ gas, B ₂ H ₆ and H ₂ gas as material gases. The p-type a-SiGe is formed by the above-described plasma CVD method using SiH ₄ gas, GeH ₄ gas, B ₂ H ₆ gas and H ₂ gas as material gases. The p-type a-Ge is formed by the above-described plasma CVD method using GeH ₄ gas, B ₂ H ₆ gas, and H ₂ gas as material gases.

  Further, in the photoelectric conversion element 200, the p-type amorphous films 111 to 11n include p-type a-SiC, p-type a-SiO, p-type a-SiN, and p-type a- in addition to p-type a-Si. SiSn, p-type a-SiGe, or p-type a-Ge may be used, and the i-type amorphous films 121 to 12n-1 may include i-type a-SiC, It may be made of any one of i-type a-SiO, i-type a-SiN, p-type a-SiSn, and i-type a-SiGe. The n-type amorphous films 131 to 13n-1 are n-type a- In addition to Si, n-type a-SiC, n-type a-SiO, n-type a-SiN, n-type a-SiSn, n-type a-SiGe, and n-type a-Ge may be used.

  That is, the p-type amorphous films 111 to 11n, the i-type amorphous films 121 to 12n-1 and the n-type amorphous films 131 to 13n-1 are each made of any of the materials shown in Table 3. Just do it.

  And the material gas when forming p-type a-SiC etc. is as having mentioned above. The reason why i-type a-Ge as the i-type amorphous films 121 to 12n-1 is excluded is also as described above.

  Further, in the photoelectric conversion element 100, the i-type amorphous films 21 to 2n-1 may be deleted and the p-type amorphous films 31 to 3n-1 may be formed in contact with the n-type single crystal silicon substrate 1. Good.

  As a result, the series resistance to the photoexcited holes in the n-type single crystal silicon substrate 1 is reduced, and the photoexcited holes pass through the p-type amorphous films 31 to 3n-1 to the electrodes 51 to 5n-1. It becomes easy to reach. Therefore, the fill factor FF is improved and the conversion efficiency of the photoelectric conversion element 100 can be further improved.

  Accordingly, the photoelectric conversion element 100 only needs to include at least the n-type single crystal silicon substrate 1, the n-type amorphous films 11 to 1n, and the p-type amorphous films 31 to 3n-1.

  Further, in the photoelectric conversion element 200, the i-type amorphous films 121 to 12n-1 may be deleted and the n-type amorphous films 131 to 13n-1 may be formed in contact with the p-type single crystal silicon substrate 101. Good.

  As a result, the series resistance to the photoexcited electrons in the p-type single crystal silicon substrate 101 decreases, and the photoexcited electrons reach the electrodes 151 to 15n-1 via the n-type amorphous films 131 to 13n-1. It becomes easy to do. Therefore, the fill factor FF is improved, and the conversion efficiency of the photoelectric conversion element 200 can be further improved.

  Therefore, the photoelectric conversion element 200 may include at least the p-type single crystal silicon substrate 101, the p-type amorphous films 111 to 11n, and the n-type amorphous films 131 to 13n-1.

  The photoelectric conversion element 100 only needs to include at least the n-type single crystal silicon substrate 1, the n-type amorphous films 11 to 1n, and the p-type amorphous films 31 to 3n-1, and the photoelectric conversion element 200 is p. The photoelectric conversion element according to the embodiment of the present invention has only to include at least a single-type single crystal silicon substrate 101, p-type amorphous films 111 to 11n, and n-type amorphous films 131 to 13n-1. A single crystal silicon substrate having a first conductivity type, and a second conductivity type provided in contact with the surface of the single crystal silicon substrate on the side opposite to the light incident side of the single crystal silicon substrate and opposite to the first conductivity type And a first amorphous film including at least a film made of an amorphous phase (p-type amorphous films 31 to 3n-1 or n-type amorphous films 131 to 13n-1), Adjacent to the first amorphous film in the in-plane direction of the single crystal silicon substrate And a second amorphous material provided in contact with the surface opposite to the light incident side of the single crystal silicon substrate and the end surface of the single crystal silicon substrate, having the first conductivity type, and comprising an amorphous phase. It is only necessary to include a material film (n-type amorphous films 11 to 1n or p-type amorphous films 111 to 11n). Here, when the single crystal silicon substrate is the n-type single crystal silicon substrate 1, the first amorphous film is an i-type amorphous film 21-2n-1 / p-type amorphous film 31-3n- 1 or p-type amorphous films 31 to 3n-1 and the single crystal silicon substrate is a p-type single crystal silicon substrate 101, i-type amorphous films 121 to 12n-1 / n-type amorphous film 131 to 13n-1 or n-type amorphous films 131 to 13n-1.

  If the photoelectric conversion element includes the single crystal silicon substrate, the first amorphous film, and the second amorphous film, the minority carriers in the photoelectric conversion element are converted into the first amorphous film by the above-described mechanism. This is because the majority carriers in the photoelectric conversion element easily reach the second amorphous film, and the conversion efficiency of the photoelectric conversion element can be improved.

  In the photoelectric conversion element 100, the n-type is the first conductivity type and the p-type is the second conductivity type opposite to the first conductivity type. In the photoelectric conversion element 200, the p-type is the first conductivity type, and the n-type is the second conductivity type opposite to the first conductivity type.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a photoelectric conversion element.

  1,101 n-type single crystal silicon substrate, 6 oxide film, 7 antireflection film, 10, 11-1n, 131-13n-1 n-type amorphous film, 21-2n-1, 40, 121-12n-1 i-type amorphous film, 20, 30, 60 resist pattern, 31-3n-1, 50, 111-11n p-type amorphous film, 41-4n, 51-5n-1, 141-14n, 151-15n -1 electrode, 100, 200 photoelectric conversion element.

Claims (7)

A single crystal silicon substrate having a first conductivity type;
A second conductivity type opposite to the first conductivity type, provided in contact with the surface of the single crystal silicon substrate on a side opposite to the light incident side of the single crystal silicon substrate, and having an amorphous phase film at least saw including a made of a first amorphous film having a plurality arranged in one cross section,
In the cross-sectional view, the surface adjacent to the first amorphous film in the in-plane direction of the single crystal silicon substrate and opposite to the light incident side of the single crystal silicon substrate, and the end surface of the single crystal silicon substrate And a second amorphous film having the first conductivity type and comprising an amorphous phase ,
In the cross-sectional view, a plurality of the first amorphous films and the second amorphous films are alternately arranged, and both ends of the surface opposite to the light incident side of the single crystal silicon substrate are arranged. The photoelectric conversion element , wherein the second amorphous film is disposed in a portion, and the second amorphous film is disposed so as to be continuous from the both end portions to the end face of the single crystal silicon substrate .   The first amorphous film is provided in contact with the surface of the single crystal silicon substrate, has only the second conductivity type, and includes only a third amorphous film made of an amorphous phase. The photoelectric conversion element according to claim 1. The single crystal silicon substrate is made of n-type single crystal silicon,
The second amorphous film is made of n-type amorphous silicon,
The photoelectric conversion element according to claim 2, wherein the third amorphous film is made of p-type amorphous silicon. The single crystal silicon substrate is made of p-type single crystal silicon,
The second amorphous film is made of p-type amorphous silicon,
The photoelectric conversion element according to claim 2, wherein the third amorphous film is made of n-type amorphous silicon. The first amorphous film includes:
A third amorphous film that is provided in contact with the surface of the single crystal silicon substrate and is made of a non-doped amorphous phase;
2. The photoelectric conversion according to claim 1, further comprising: a fourth amorphous film provided on the third amorphous film and having the second conductivity type and having an amorphous phase. element. The single crystal silicon substrate is made of n-type single crystal silicon,
The second amorphous film is made of n-type amorphous silicon,
The third amorphous film is made of i-type amorphous silicon,
The photoelectric conversion element according to claim 5, wherein the fourth amorphous film is made of p-type amorphous silicon. The single crystal silicon substrate is made of p-type single crystal silicon,
The second amorphous film is made of p-type amorphous silicon,
The third amorphous film is made of i-type amorphous silicon,
The photoelectric conversion element according to claim 5, wherein the fourth amorphous film is made of n-type amorphous silicon.

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