JPH06252496A - Formation of quantum wire structure - Google Patents

Abstract

PURPOSE:To provide a method for forming a quantum wire structure easily without particular minute pattern processing. CONSTITUTION:For obtaining a semiconductor substrate 1 on which a compound semiconductor and a semiconductor layer of wide forbidden band are to be formed by deposition and which comprises recessed grooves 3 formed on the surface, a semiconductor base 1 on whose surface a mask 2 is arranged which comprises a pattern in which uncoated zones exist on both sides of a coated zone and those extend in parallel in longitudinal direction. After effecting mesa etching of a mask forming plane of the semiconductor base 1, a semiconductor layer 5 is deposited to form recessed grooves 7 on the surface while leaving the mask.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a quantum wire structure which becomes a light emitting portion in a semiconductor light emitting device such as a semiconductor laser.

[0002]

2. Description of the Related Art Some semiconductor light emitting devices such as semiconductor lasers have a quantum wire structure, and in this case, they are characterized by a sharp emission spectrum. The quantum wire structure has a wide forbidden band on the upper and lower surfaces of a compound semiconductor layer deposited and formed in a concave groove (U groove or V groove) on the surface of a semiconductor substrate and continuing along the longitudinal direction of the concave groove ( It has a semiconductor layer structure in which a semiconductor layer (having a large energy gap) is installed, and when a light emitting device is formed, a thin linear light emitting portion is generated along the longitudinal direction of the compound semiconductor layer. is there.

This quantum wire structure can be formed, for example, by using a molecular beam epitaxy (MBE) method or a metal organic deposition (MOCVD) method and using a compound semiconductor of GaAs and AlGaAs as a material as follows. Yes (Journal of Applied Physics JAP No. 71
Pp 533-535, 1992). As shown in FIG. 4A, a 200 Å-thick SiO film is formed by CVD on the (100) surface of the GaAs substrate 5l whose surface is the (100) surface.
_{The two} films are patterned by electron beam lithography and wet etching to form a mask 52 of SiO ₂ film.
On the surface of the GaAs substrate 51, a long SiO ₂ film having a width of 100 Å whose longitudinal direction is the <01-1> direction is 100.
A mask 52 having a pattern in which the masks 52 are arranged in parallel at an interval of 0Å, the uncovered regions are adjacent to each other on both sides of the covered region, and both regions are parallel to the longitudinal direction is provided.

After forming the mask 52, as shown in FIG. 4B, GaAs 53 is deposited by MOCVD,
As shown in FIG. 4C, a semiconductor substrate 60 having a V groove 61 on its surface is manufactured. V groove 61 in semiconductor substrate 60
Is a smooth (111) A plane of GaAs53. After this, as shown in FIG. 4D, AlGaAs
After the layer 62 is deposited, the GaAs layer 63 is repeatedly deposited to form a multi-layered quantum wire structure as shown in FIG. In the case of FIG. 4E, a GaAs layer 63 deposited and formed in the V-shaped groove 61 and continuing along the longitudinal direction of the groove.
The AlGaAs 62 having a wide forbidden band on the upper and lower surfaces constitutes a quantum wire structure for one layer. GaAs layer 63 is more Al
The optical refractive index is larger than that of GaAs62.

[0005]

However, the above-mentioned conventional method for forming a quantum wire structure is very difficult to carry out. It is necessary to perform a special fine pattern processing of several hundred Å by the electron beam lithography technology and the wet etching method, and this fine pattern processing is not really successful.

In view of the above circumstances, it is an object of the present invention to provide a method capable of easily forming a quantum wire structure without special fine pattern processing.

[0007]

To solve the above problems, according to the present invention, a compound semiconductor layer and a wider forbidden band than the compound semiconductor layer are formed on the groove formation surface of a semiconductor substrate having a concave groove formed on the surface thereof. By depositing a semiconductor layer and forming a semiconductor layer structure in which a semiconductor layer having a wide forbidden band is arranged on the upper and lower surfaces of the compound semiconductor layer in the concave groove along the longitudinal direction of the concave groove, the compound is formed. In a method of forming a quantum wire structure in which a thin light emitting portion is generated along a longitudinal direction in a semiconductor layer, a semiconductor substrate having concave grooves formed on the surface thereof is obtained by forming a quantum wire structure on both sides of a covered area. After performing a mesa etching on the mask forming surface of the base material using a semiconductor base material having a mask having a pattern in which the coating areas are adjacent to each other and the both areas are parallel to each other in the longitudinal direction. The concave grooves of the semiconductor layer while leaving the mask is characterized by depositing as possible to the surface.

The semiconductor substrate used in the present invention is G
Examples include aAs wafers and silicon single crystal wafers.
Not limited to these. The mask provided on the surface of the semiconductor substrate may be a mask of a silicon nitride film or a silicon oxide film, and the semiconductor layer deposited so that a concave groove can be formed on the mask formation surface may be a GaAs layer. , But not limited to these.

Examples of the compound semiconductor layer and the semiconductor layer having a wide forbidden band disposed on the upper and lower surfaces thereof in the present invention include, but are not limited to, the GaAs layer for the former and the AlGaAs layer for the latter.

[0010]

According to the method of forming the quantum wire structure of the present invention, as shown in FIG.
As shown in FIG. 5, the semiconductor layer 5 is deposited on the remaining surface of the mask 2 after the mesa etching of the semiconductor substrate on the surface of which the mask 2 having a pattern in which the covered area and the uncovered area are adjacent and parallel to each other is provided. In this case, the cavities 6, 6 ... Continued on the mask 2 in the direction perpendicular to the drawing surface for a long time.
Run parallel to each other, and minute V-grooves (concave grooves) 7 much narrower than the width of the mask 2 are formed along the positions of the cavities 3 and 3 on the surface of the semiconductor layer 5. A quantum wire structure is formed by using the fine V groove 7. Conventionally, it was necessary to form a special fine pattern for forming the concave groove, but in the case of the present invention, the width of the mask 2 is wider than the width of the V groove 7 formed on the surface of the semiconductor layer 5, No need for fine pattern processing.
Even after the V-groove 7 is formed, no special fine patterning is required, and as a result, the quantum wire structure can be produced without requiring any special fine patterning.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. This invention is not limited to the following embodiments. First, as shown in FIG. 2, a mask 2 is formed on the (100) plane of a GaAs substrate 1 whose surface is the (100) plane, and mesa etching such as wet etching is applied to the uncovered area. A recess 3 is formed which continues in a direction perpendicular to the surface. The mask 2 has a pattern in which coated areas and uncoated areas appear alternately, and both areas are parallel to the longitudinal direction (direction perpendicular to the drawing surface).
It can be provided by forming an iO ₂ film and patterning it into a stripe shape having a width and an interval of 7 μm by using a photolithography method. The recess 3 formed by mesa etching had a depth of about 5 μm.

Subsequently, as shown in FIG. 3, with the mask 2 left on the mesa-etched surface of the GaAs substrate 1, a GaAs layer 5 is deposited by a metal organic deposition method so that a V groove 7 can be formed on the surface. Form. Thus, the semiconductor substrate 10 having the V groove 7 formed on its surface is completed. When the height of the GaAs layer 5 from the mask 2 is 5 μm or more, a cavity 6 is formed.
And the V groove 7 can be formed.

As shown in FIG. 1, an AlGaAs layer (semiconductor layer) 11, a GaAs layer (compound semiconductor layer) 12, and an Al layer are formed on the surface of the semiconductor substrate 10 on which the V-groove 7 is formed, as shown in FIG.
If the GaAs layer (semiconductor layer) 13 is deposited and grown in order,
The quantum wire structure is completed. In the case of a semiconductor laser,
It goes without saying that the electrodes are provided on the upper and lower surfaces. In the quantum wire structure in FIG. 1, the GaAs layer 1
In the V-shaped portion along the V groove 7 of 2, there are AlGaAs layers (semiconductor layers) 11 and 13 having a wide forbidden band at the top and bottom, and
This is a structure in which a thin linear light emitting portion is generated along the longitudinal direction on the bottom of the V-shaped portion of the s layer 12.

The present invention is not limited to the above embodiment. For example, as shown in FIG. 1, an AlGaAs layer (semiconductor layer) 1
1. After the GaAs layer (compound semiconductor layer) 12, again
The AlGaAs layer (semiconductor layer) 11 and the GaAs layer (compound semiconductor layer) 12 may be repeatedly deposited and grown to make the quantum wire structure multi-layered. GaAs substrate 1 is S
In the case of an i base material, a thin lattice mismatch relaxation layer is deposited and formed on the inner surface of the recess formed by mesa etching, and then Ga
The As layer 5 may be deposited such that a concave groove is formed on the surface. InGaAs is used as the lattice mismatch relaxation layer.
A strained superlattice structure composed of / GaAs or GaAsP / GaAs can be used.

[0015]

According to the method of forming a quantum wire structure of the present invention, since the width of the mask may be wider than the width of the concave groove formed on the surface of the semiconductor layer, no special fine pattern processing is required and the quantum wire structure is not required. Can be easily formed and is very useful.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a quantum wire structure formed in an example.

FIG. 2 is a cross-sectional view showing a mesa etching process in an example.

FIG. 3 is a cross-sectional view showing a V-groove forming step in the example.

FIG. 4 is an explanatory diagram showing a state when a conventional quantum wire structure is formed.

[Explanation of symbols]

 1 GaAs Base Material (Semiconductor Base Material) 2 Mask 3 Recess 5 GaAs Layer 6 Cavity 7 V Groove 11 AlGaAs Layer (Semiconductor Layer) 12 GaAs Layer (Compound Semiconductor Layer) 13 AlGaAs Layer (Semiconductor Layer)

Claims (1)

[Claims] 1. A compound semiconductor layer and a semiconductor layer having a wider forbidden band than the compound semiconductor layer are deposited and formed on a groove forming surface of a semiconductor substrate having a concave groove formed on the surface thereof, and the concave groove is formed in the concave groove. By forming a semiconductor layer structure in which semiconductor layers having a wide forbidden band are arranged on the upper and lower surfaces of the compound semiconductor layer along the longitudinal direction of the compound semiconductor layer, thin linear light emitting portions are generated in the compound semiconductor layer along the longitudinal direction. In the method of forming a quantum wire structure as described above, in obtaining a semiconductor substrate in which a concave groove is formed on the surface, uncovered regions are adjacent to each other on both sides of the covered region, and both regions continue in parallel to the longitudinal direction. Using a semiconductor base material having a mask having a pattern on the surface, after performing mesa etching on the mask formation surface of the base material, the semiconductor layer can be formed with the concave groove on the surface while leaving the mask. A method for forming a quantum wire structure, characterized in that the quantum wire structure is deposited.