JPS6171621A - Manufacture of semiconductor - Google Patents

Abstract

PURPOSE:To enable epitaxial growth of a semiconductor such as silicon which has excellent electrical characteristic and crystallizability, by a method wherein inert helium gas is employed as a carrier gas in place of hydrogen gas in the early stage of epitaxial growth. CONSTITUTION:Sapphire substrates 2 for epitaxial growth of a semiconductor such as silicon are mounted on a heating plate 3 and placed in a bell jar 1. A helium has valve 6 is first opened. In consequence, a material gas mixture of helium has contained in a helium container 7 and monosilane gas contained in a monosilane gas container 8 is supplied through a material gas inlet 5 to the sapphire substrates 2 heated by an induction heating coil 4. When a silicon film 9a of 100-500Angstrom thickness has been epitaxially grown on the surface of each sapphire substrate 2 as a result of the supply of the material gas mixture containing helium gas, the helium gas valve 6 is closed, and a hydrogen gas valve 10 is opened to supply a material gas mixture of hydrogen gas and the monosilane gas to the sapphire substrates 2 from the gas inlet 5.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a semiconductor device 1 in which a semiconductor such as silicon is epitaxially grown on an oxide single crystal substrate or an oxide single crystal film formed on a silicon 111 crystal board. Book manufacturing method (
Two matters.

(Prior art) Generally, in semiconductor devices that use an insulator such as silicon oxide to electrically isolate elements (isolation run) instead of using a concave junction isolation method, oxide single crystal substrates or silicon A semiconductor such as silicon is epitaxially grown on a single crystal oxide film formed on a single crystal substrate, and elements are formed in the semiconductor layer formed by this epitaxial growth.

Conventionally, for example, in an SOS (silicon-on-silicon) type semiconductor device in which elements are formed on a sapphire substrate, which is an oxide single crystal, when semiconductors are epitaxially grown on silicon or the like on the oxide substrate, A gas such as silane, silicon tetrachloride or silane is used as a raw material gas, and hydrogen gas is used as a carrier gas.

By the way, epitaxial growth of semiconductors such as silicon requires high temperatures ranging from 950'(:') to 1200' C, which causes a reduction reaction between the carrier gas hydrogen and the oxide single crystal. It is known that a part of the surface of the oxide is decomposed into metal and oxygen.For example, when a Su7fire substrate is used as an oxide single crystal, the following reduction reaction occurs on the surface of the Su7fire substrate. is thought to be happening.

Sheet 1゜ + ノ＼1′″, ○, → A(′2()
+2H2 () or 2 + AO, = 03 → 2 A (l +02 + 8.0) The metal and oxygen decomposed from this reduction reaction 1 mix and diffuse into the semiconductor layer during epitaxial growth, and Significantly inhibits properties and crystallinity.

(Object of the Invention) The present invention was made in the spring in view of the above-mentioned problems in semiconductor manufacturing, and is based on an oxide 111 crystal film formed on an oxide single crystal substrate or a silicon single crystal substrate. It is an object of the present invention to provide a method for manufacturing a semiconductor, which suppresses the reduction reaction of silicon and epitaxially grows a semiconductor such as silicon, which has good electrical characteristics and crystallinity.

(Structure of the Invention) Therefore, in the present invention, when epitaxially growing a semiconductor such as silicon on an oxide single crystal substrate or an oxide single crystal film formed on a silicon single crystal substrate, carriers are This is characterized by the use of inert helium gas instead of hydrogen gas as gas. That is, the present invention suppresses a reduction reaction on the surface of an oxide single crystal film formed on an oxide single crystal substrate or a silicon single crystal substrate by using inert helium gas as a carrier gas in the early stage of semiconductor epitaxial growth. As a result, epitaxial growth can be performed without contamination due to reduction reactions.

(Example) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Typical epitaxial devices currently in use include the induction heating horizontal reactor shown in Figure 1(a), the induction heating vertical pancake reactor shown in Figure 1(b), and the induction heating vertical pancake reactor shown in Figure 1(c). There are reactors and other cylinders that use radiation heating.

For both types of epitaxial equipment, Beltsuya 1
A heating plate 3 on which a wafer 2 of an oxide single-crystal substrate or a silicon single-crystal substrate with an oxide single-crystal film formed on the surface is placed is placed inside the wafer 95 with an induction heating coil ↓.
A raw material is introduced from the raw material gas inlet 5 into the wafer 2 which has been heated to +1' (: to 1200'C for 6 liters).
A semiconductor such as silicon is epitaxially grown thereon.

The present invention may be implemented in any of these three types of epitaxial devices.

Next: 1. Using these epitaxial devices to epitaxially form a silicon semiconductor on a sapphire substrate [<
, ': An example will be described in which it is set.

First, a 7-layer substrate (wafer 2) on which a silicon semiconductor is grown epitaxially is placed on a heating plate 3 and housed in a belt heater 1.

First, because we use helium as the carrier gas,
Open the helium gas valve 6 and mix the helium gas in the helium container 7 and the monosilane gas in the monosilane gas container 8 (
The raw material gas mixed with Si) (,) is heated to 950'C to 12°C by the raw material gas inlet 5 or the induction heating coil 4.
+) Supply to the 7-fire substrate 2 heated to 0°C.

By supplying this raw material gas mixed with helium gas, the second
As shown in the figure (,), 100 yen is applied to the surface of the 7-layer substrate 2.
When the silicon semiconductor 9a is grown epitaxially to a film thickness of angstroms to 500 angstroms,
The helium gas valve 6 is closed, the hydrogen gas valve 10 is opened, and a raw material gas mixture of hydrogen gas in the hydrogen container 11 and monosilane gas in the monosilane gas container 8 is supplied from the raw material gas inlet 5 to the sapphire substrate 2, as shown in FIG. As shown in (a), a silicon semiconductor 9b is successively epitaxially grown on the semiconductor 9a to a required thickness.

This shift is caused by the fact that at the time the carrier gas is switched from helium gas to hydrogen gas, the surface of the 7T layer substrate 2 is already covered with silicon semiconductor devices, so the surface of the 7T layer substrate 2 is covered with hydrogen gas. It is possible to form semiconductors 9a and 91 with good electrical properties and crystallinity without being reduced by gas.

・Eic light is aluminum '° like Saffire board 2.
On the surface of the silicon single crystal substrate 12, as shown in FIG. 2 (1), on the surface of the silicon single crystal substrate 12.
It is also possible to use a wafer 2 on which a monocrystalline film 13 of a monocrystalline arsenide such as stabilized Norfunya or the like is formed.

(Effects of the Invention) As is clear from the detailed description above, the present invention has the following effects:
Inert helium gas is used as a carrier gas in the early stage of semiconductor epitaxial growth to suppress the reduction reaction on the surface of the oxide single crystal formed on the oxide single crystal substrate or silicon single crystal substrate on which the semiconductor is epitaxially grown. Therefore, a semiconductor with good electrical characteristics and crystallinity can be epitaxially grown without contaminating the semiconductor due to the reduction reaction of the oxide single crystal.

In addition, in the present invention, helium gas, which is one of the fewest resources on earth and is expensive, is used for the first time, or the use of helium gas is used to the minimum necessary in the initial stage of epitaxial growth, and thereafter, cheap hydrogen gas is used. Therefore, semiconductor devices can be manufactured industrially at low cost.

[Brief explanation of the drawing]

FIG. 1(a), FIG. 1(1+), and FIG. 1(C) are explanatory diagrams of the semiconductor book manufacturing apparatus used in the present invention, FIG. 2(,), and FIG. 2(I), respectively. ) are cross-sectional views showing the structure of semiconductors manufactured according to the present invention. 2... Wafer, 5... Raw material gas introduction row,
6... Helium gas valve, 7... Helium container, 8... More silane gas container, 9a, 9b.
・・・Semiconductor, 10...Hydrogen is Subaru, 11...
・Hydrogen container, 12...Silicon single crystal substrate, 13
...Oxide single crystal film.

Claims (1)

[Claims] (1) In the process of epitaxially growing a semiconductor such as silicon on an oxide single-crystal substrate or an oxide single-crystal film formed on a silicon single-crystal substrate, it is used as a carrier gas for the semiconductor at the initial stage of the epitaxial growth of the semiconductor. A semiconductor manufacturing method characterized by using helium gas and changing it to hydrogen gas midway through to epitaxially grow a semiconductor continuously.