JPS5863138A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To form the SiO2 film with stable structure, excellent reproducibility, low cost and high reliability as a product by a method wherein the process forming SiO2 film by means of ventilating monosilane (SiH4) and oxgen after preliminarily ventilating phosphine or a gas mixed with phosphine in a reactor is included. CONSTITUTION:The GaAs substrate 11 is inserted into a reactor comprising quartz and the like to be heated up to specified temperature of around 300- 500 deg.C under inactive atmosphere such as Ar etc. or weak reducing atmosphere including a bit of hydrogen (H2) etc. Then PH3 is introduced into said reactor out of SiH4, O2, phosphine (PH3) gas flow rate wherein the phosphorus containing ratio in case of forming SiO2 film is preliminarily set up to be 3-10mol%. The SiO2 film 13 containing 3-10mol% of phosphorus may be formed after specified time elapsed by means of simultaneously introducing SiH4 and O2 into reactor for thermal cracking oxidation of SiH4 while ventilating PH4 after the time saturating the reactor with PH3 elapsed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device, and in particular to a method for manufacturing a semiconductor device, in particular a method for manufacturing a semiconductor device using a group IV compound such as gallium arsenide (GaAs) or germanium (
The present invention relates to a method of forming a silicon dioxide (Sing) film on a semiconductor substrate whose main component is Ge) or the like.

For example, when forming a 0.8μ band laser diode element, aluminum (Ag) and impurities such as germanium (Ge) or tin (Sn) are added to the QaAs substrate.
After forming all the multilayer epitaxial layers containing an appropriate number, 5
8 i 0 formed on the i02 film and through photo-etching technology
A method is used in which the internal structure of the laser diode element is formed by providing an opening in the two films and using the 5i02 as a diffusion mask to thermally diffuse the zinc (Zn)' to a predetermined depth.
The 102 film is usually formed by a vapor phase growth method in which monosilane (8iH4)k is thermally decomposed by heating to 300 to 500°C in an oxygen (02) atmosphere, or silicon oxide (Si
A method has been adopted in which a 5in2 film is deposited on the substrate by high frequency sputtering in a reduced pressure atmosphere of Arcon (Ar) at about k 10-'' to 10-'' Torr.

However, in the vapor phase growth method for obtaining 8i02 by thermal decomposition in SiH4to2, the gallium (Ga) on the GaAs (e-generating component) substrate is oxidized, so that during the subsequent thermal diffusion of Zn, the GaAs surface and the S10□ film are Creeping diffusion between the two occurs, causing the diffusion pattern to expand and deviate from the stepped shape, increasing the threshold current, which is one of the main performance characteristics of a laser diode element.
a A s The surface condition of the substrate, the partial pressure ratio of 5iH4102, the growth temperature of the 5i02 film, the Zn diffusion temperature, Z
It is almost impossible to control the degree of creeping diffusion because it is influenced by many factors such as the atmosphere to which the surface of the GaAs substrate is exposed during n diffusion. Therefore, it is extremely difficult to achieve the full designed laser diode performance.

In addition, 5iOz was formed on a GaAs substrate by high-frequency sputtering of SiO etc. in a reduced pressure Ar atmosphere.
It is difficult to form an amorphous film, and it is difficult to obtain a film of sufficient quality to function as a mask for Zn diffusion. That is, the energy of high frequency sputtering is GaA
s Sputtering damage to the surface of the substrate is limited to a level that does not cause noise, so it is not possible to form a homogeneous amorphous 5i02 layer by slightly heating the substrate.If pinhole-like diffusion occurs during diffusion and is significant, the design pattern may be Sometimes you may find yourself in a situation where it cannot be achieved. Therefore, some measures are taken, such as forming a SiO2 conversion film by sputtering and then layering a 5i02 film by vapor phase growth to form the entire mask for Zn diffusion, but this method doubles the entire process. In addition, prior to diffusion, the two layers of 5i02 film must be completely opened, but because the etching speed of the different 8i0z film is different, it is said that it is difficult to fully form the desired diffusion mask pattern, especially in the case of fine shapes. contains problems.

The above defects are caused by GaAs, Indium Phosphate (InP)
) IN-V group compounds, germanium (Ge), etc.
i 02 When forming into cash, silicon (St″L
J:.

Since continuous connective tissue is not formed as in the case of forming a 5i02 film, the present invention, which occurs widely and generally, has been made in view of the above, and is a novel method that provides a stable structure that is efficient, inexpensive, and has high product reliability. The purpose of this invention is to provide a complete method of manufacturing a semiconductor device, which mainly involves forming a 5iOz film on a QaAs substrate or the like.

According to the present invention, a group IV compound or germanium (Ge
)'e Ihi silicon dioxide (
When forming a Si02) film, the substrate is maintained at 300 to 500°C in an inert atmosphere or a reducing atmosphere, and phosphine (PHa) or a phosphine mixed gas is passed into the reactor in advance, and then monosilane (SiH4) and oxygen(
02) A method for manufacturing a semiconductor device featuring a backing metal including a step of forming an 8102 film through complete ventilation is obtained.

Hereinafter, the present invention will be explained in detail by taking as an example the method for manufacturing a laser diode element described above.

QaAs Eight on the board! and added impurities (Ge or Sn
etc.) After forming the entire multilayer epitaxial layer containing the entire designed amount, the substrate is inserted into a reactor made of quartz or the like, and placed in an inert atmosphere such as Ar or a weakly reducing atmosphere containing a small amount of hydrogen (H2), etc. The temperature is then raised to a predetermined temperature of about 300 to 500°C. After that, phosphorus (
SiH, the content of P) is set to be about 3 to ole 10 .

5-02. Of the phosphine (PHs) gas flow rate, PH3 is introduced into the reactor. After a period of time for PH3 to spread throughout the reactor, SiH4 and 02 are introduced into the reactor at the same time while still being vented to cause a thermal decomposition oxidation reaction of 5iFI4. , 5i02 containing about 3-10% P
A membrane is obtained.

Usually 8i02 film grown by 5iH4102 system is SiH
4. In order to completely prevent the precipitation of Si fine particles due to thermal decomposition (thermal decomposition of SiH4 alone occurs at an even higher temperature, or the decomposition reaction is accelerated by 02 mixed air), the process is carried out under slightly 02-rich gas conditions, which solves the above-mentioned problem. However, when 5iH4102 is introduced in a reducing PH atmosphere, the Sing formation reaction and the P2O5 formation reaction proceed simultaneously, resulting in the formation of QaAs.
It is thought that the substrate surface is not directly exposed to 02 in a heated state, and S Io 2 containing all P components begins to be generated directly. On the other hand, a 5i02 film containing about 3 to 1 Q mole% of P components, Normal S i Ha / 02
Since it contains almost the same chemical etching performance as the Sing film grown in the vapor phase depending on the system, there is no etching problem during photoetching and mask patterns can be formed efficiently. It is known that by containing a small amount of , a more homogeneous vapor-grown 8i02 film with less distortion can be formed, and pinhole-like mask defects do not occur during diffusion. Therefore, in the subsequent Zn diffusion, G a A
s It is possible to stably form a Zn diffusion layer in the multilayer epitaxial layer of the substrate with no creeping diffusion on the narrow surface of the substrate, and the Zn diffusion layer is consistent with the design value.

Furthermore, if the laser diode element is completely completed through the subsequent metallization process, will it perform as designed? Therefore, it is possible to realize a stable and inexpensive laser diode element with reproducibility.

[Brief explanation of the drawing]

Schematic diagram 1 Conceptual cross-sectional view of laser diode element structure when using conventional SiO2 film formation technology (a): When performing Zn n diffusion using a 5i02 film formed using the conventional vapor phase growth method as a diffusion mask. Conceptual diagram (b): 51 formed using the conventional Subanotari/G method
FIG. 2 is a conceptual diagram of the case where Zn is diffused using the 02 film as a diffusion mask. FIG. 1.11...GaAs substrate, 2.12...
...Multilayer epitaxial layer GaAs (A-g,
Sn, Qe). 3... 5i02 film produced by conventional vapor phase growth method,
3'...5 by conventional high frequency sputtering
i02 film, 13...5102 film by the present invention (vapor phase growth method), 4...8i02 film opening, 5.15...5i02 film opening It is diffused through the hole 4 and 7' (Zn diffusion layer, 5'...S i
02 Diffusion layer diffused through membrane pinhole.

Claims (1)

[Claims] When forming a silicon dioxide (SiO2) film on a semiconductor substrate containing 1-V group compound or germanium (Gel) as the main component, the substrate is held at 300 to 500°C in an inert atmosphere or a reducing atmosphere and phosphine is added. (PHa
) or phosphine mixed gas into a reactor in advance, and then monosilane (SiH4) and oxygen (02)Th are vented to form a StO film.