JPH0752713B2 - Method for growing compound semiconductor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for growing a compound semiconductor, and more particularly to a method for epitaxially growing a compound semiconductor layer on a semiconductor substrate of silicon (hereinafter referred to as Si).

(Prior Art) Generally, gallium arsenide (hereinafter referred to as GaAs) is formed on a semiconductor substrate such as Si.
In the case of growing compound semiconductors, such as Applied Physics Le
38 (10), 15May1981, pp779-781, and growth through a buffer layer such as a Ge film, or literature Nikkei Microdevice January 1986 (Showa 61).
(Published January 1, 2013) As disclosed in pp113-127, a compound semiconductor layer is directly formed on the substrate by a metal organic chemical vapor deposition (hereinafter referred to as MOCVD) method or a molecular beam epitaxial (hereinafter referred to as MBE) method. Are growing.

(Problems to be Solved by the Invention) However, in such a method for growing a compound semiconductor, the thermal expansion coefficient of the compound semiconductor is generally larger than the thermal expansion coefficient of the semiconductor substrate such as Si, and the high growth temperature of the compound semiconductor When the temperature was lowered to about room temperature, a strong tensile stress was applied to the compound semiconductor growth layer. For this,
If the substrate warps concavely in the direction of the growth surface, or if the growth film becomes thick, there is a problem that the stress causes cracks in the growth layer.

The present invention aims to reduce the stress due to the difference in the coefficient of thermal expansion between the Si substrate and the compound semiconductor, and to reduce the occurrence of warpage of the wafer and cracks when the film pressure of the compound semiconductor growth layer is increased. To do.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a backside of a Si semiconductor substrate with Si having a smaller coefficient of thermal expansion than the semiconductor substrate.
A backside film such as O ₂ is deposited at a predetermined temperature, and a compound semiconductor layer such as GaAs is grown on the surface of this semiconductor substrate at a temperature higher than the predetermined temperature.

(Operation) As described above, according to the present invention, the back surface film having a small thermal expansion coefficient is deposited on the back surface of the semiconductor substrate at a predetermined temperature. When the temperature is higher than the temperature, a convex warp occurs on the substrate side, and since the compound semiconductor is further grown in this state, when the temperature of the substrate warped by the convex is lowered to about room temperature, the force to return to the original works, A flat substrate can be obtained.

(Embodiment) FIGS. 1A to 1C are sectional views of a substrate for explaining an embodiment of the present invention. Hereinafter, description will be given with reference to the drawings.

First, as shown in FIG. 1 (A), a Si substrate 1 is prepared, and a SiO ₂ film 2 is deposited on the back surface of the Si substrate 1 at a temperature of about 30 ° C. to a thickness of about 1 μm by using a sputtering method. .

Next, when the Si substrate 1 is put into an apparatus for growing a GaAs layer and the growth temperature of the GaAs layer is 600 ° C. to 750 ° C., the coefficient of thermal expansion of Si (2.4 × 10 ⁻⁶ / deg) is SiO ₂ Coefficient of thermal expansion (0.4
Since it is larger than × 10 ^-6 / deg), as shown in FIG. 1 (B), a convex warp occurs on the Si substrate 1 side.

In this state, the GaAs layer 3 is grown on the surface by the MOCVD method, and when the Si substrate 1 is cooled to room temperature (25 ° C.), the Si substrate 1 which is convexly warped is shown in FIG. 1 (C). Return to flat as shown in. Actually, the thermal expansion coefficient of GaAs is about 6 x 10
^Since it is ^-6 / deg, if the SiO ₂ film 2 is deposited on the Si substrate 1 at room temperature, the GaAs layer 3 is grown and then cooled to about room temperature. It becomes slightly concave in the direction of. However, the SiO ₂ film 2 even when deposited at a sufficiently lower temperature than the growth temperature of higher and GaAs layer 3 at room temperature or at room temperature, when compared with the case where there is no SiO ₂ film 2 at room temperature from the temperature of growing the GaAs layer 3 Warp when the temperature is lowered to

In the embodiment of the present invention, the deposition temperature of the SiO ₂ film 2 is preferably lower than room temperature, and the film thickness thereof is preferably thick.

The GaAs layer 3 was grown by the MOCVD method at a temperature of 600 ° C. to 750 ° C., but GaAs of about 20 nm was grown at a temperature of about 400 ° C. and then grown to a predetermined thickness at a temperature of about 750 ° C. The growth can be performed by a method having a temperature gradient, and another growth method can be used as long as it is a good epitaxial growth method such as the MBE method.

Further, in the embodiments of the present invention, the case where the GaAs layer is grown on the Si substrate has been described, but since all compound semiconductors have a larger thermal expansion coefficient than Si, it can be applied to the case of growing other compound semiconductors.

(Effects of the Invention) As described above, according to the present invention, when a compound semiconductor is grown on a Si substrate, it is possible to reduce warpage due to a difference in thermal expansion coefficient between the substrate and the compound semiconductor growth layer. ,
A good device can be formed on the grown compound semiconductor with a good yield, and since it can be used for a large area substrate, a high quality large area compound semiconductor growth layer can be obtained, It can be used to manufacture various devices.

[Brief description of drawings]

1 (A) to 1 (C) are sectional views of a substrate for explaining an embodiment of the present invention. 1 ... Si substrate, 2 ... SiO ₂ film, 3 ... GaAs layer.

Claims (3)

[Claims] 1. A step of preparing a silicon semiconductor substrate, a step of depositing a backside film having a thermal expansion coefficient smaller than that of the semiconductor substrate at a predetermined temperature on the backside of the semiconductor substrate, and a compound on the surface of the semiconductor substrate. And a step of growing the semiconductor layer at a temperature higher than the predetermined temperature, the method of growing a compound semiconductor. 2. The method for growing a compound semiconductor according to claim 1, wherein the back surface film is a silicon oxide film. 3. The method for growing a compound semiconductor according to claim 1, wherein the compound semiconductor layer is a gallium arsenide layer.