JPH0618174B2 - Semiconductor substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention mainly relates to improvement of a semiconductor substrate.

(B) Conventional Technology SOS (silicon on sapphire) substrates have come to be used as insulator substrates for semiconductors instead of silicon substrates. This is formed by epitaxially growing a silicon thin film on a sapphire single crystal substrate, and facilitates element isolation (isolation) required for integrated circuit fabrication, and by reducing the wiring capacitance and diffusion capacitance, The aim is to increase the density and speed of integrated circuits.

(C) Problems to be solved by the invention However, at high temperature on a sapphire substrate, for example,
When silicon is epitaxially grown, a part of the sapphire substrate is reduced by hydrogen used as a carrier of the source gas, and the silicon film formed on the sapphire substrate is doped with metal Al or oxygen to contaminate the silicon film. There is. Moreover, the lattice spacing between the epitaxial silicon and the substrate sapphire is significantly different (about 10%), and misfit dislocations are contained at a high density, which lowers the crystallinity of the epitaxial silicon. Therefore, the electrical characteristics of the device formed on the silicon semiconductor layer epitaxially grown on the sapphire substrate are significantly deteriorated. Furthermore, the sapphire substrate itself is more expensive than other semiconductor substrates.

The present invention has been made in consideration of such circumstances and provides a high-performance and inexpensive semiconductor substrate.

(D) Means for Solving the Problems The present invention provides a silicon substrate, a stabilized zirconia single crystal film coated on the silicon substrate, and a silicon substrate coated with the stabilized zirconia single crystal film on an O ₂ substrate. A semiconductor substrate comprising a silicon substrate and a SiO ₂ film formed between the stabilized zirconia single crystal film by heat treatment in an atmosphere.

The stabilized zirconia single crystal film is made of zirconium oxide Zr.
O in _{2, Y 2 O 3, MgO} , CaO, Sm 2 O 3, G
It is preferable to use a single crystal film formed by adding one or more of d ₂ O ₃ , Tb ₂ O ₃ , Yb ₂ O ₃ , Sc ₂ O _{5 and the} like as a stabilizer.

(E) Working The surface of the semiconductor substrate is covered with a stabilized zirconia film of oxide single crystal. Therefore, since it is stable at high temperature, reduction reaction does not occur and the epitaxially grown semiconductor layer is contaminated unlike the sapphire substrate. Even if the stabilized zirconia is a thin film, SiO ₂ formed between the stabilized zirconia film and the silicon substrate by thermal oxidation.
The layer plays a role of improving electric characteristics, and by using the silicon substrate, the residual stress due to the difference in thermal exaggeration ratio can be reduced.

(F) Embodiment Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. The present invention is not limited to this. 1 (a) to 1 (c) are explanatory views showing the manufacturing process and structure of an embodiment of the present invention.

First, as shown in FIG. 1 (a), a substrate treatment is performed to remove the influence of the natural oxide film existing on the surface of the silicon substrate (1). Before processing the substrate in this embodiment, HCl was previously used.
And H ₂ O ₂ and H ₂ O are dissolved in a ratio of 3: 1: 1, 90
The substrate surface-treated by immersing it in a solution heated to ~ 100 ° C for 5 to 10 minutes is vacuumed (3 × 10 ^-5 pa) in a sputtering system,
A method of heat treatment at ℃ for 30 minutes was used.

Next, as shown in FIG. 1 (b), C is deposited on the entire surface of the silicon substrate (1).
VD method, sputtering method, atomic layer epitaxy method, ICB method, low pressure C
Single crystal stabilized zirconia film by either VD method (2)
To cover. In this embodiment, the silicon substrate (1
A stabilized zirconia film 2 was formed on the entire surface of (00) 1 by a reactive magnetron sputtering method using Ar + O ₂ gas. The sputter is gas pressure (Ar + O ₂ ) 0.5pa, R
Under the conditions of f output of 4 W / cm ² and substrate temperature of 900 ° C., a cubic single crystal stabilized zirconia film 2 was grown to a film thickness of 3000 Å. The stabilization of the zirconia film is
As a stabilizer in zirconium oxide ZrO ₂ , yttrium oxide Y ₂ O ₃ , magnesium oxide MgO, calcium oxide CaO, samarium oxide Sm ₂ O ₃ , gadolinium oxide Gd ₂ O ₃ , terbium oxide Tb ₂ O ₃ , ytterbium oxide Yb. ₂ O ₃ , scandium oxide Sc ₂ O
It was carried out by adding about 10 mol% of one or a plurality of ₅ or the like to obtain a cubic single crystal film at a growth temperature of 550 ° C to 1000 ° C.

Next, as shown in FIG. 1 (c), thermal oxidation (for example, dry
The SiO ₂ layer 3 is formed between the silicon substrate 1 and the stabilized zirconia film 2 by performing O ₂ oxidation, steam oxidation, pyrogenic oxidation, or the like. In this example, steam oxidation was carried out at 900 ° C. for 1 hour to obtain 1500
The Å SiO ₂ film 3 was formed. That is, the SiO ₂ film 3 was formed at the interface between the silicon substrate 1 and the stabilized zirconia film 2 by utilizing the fact that the stabilized zirconia film 2 is an oxygen conductor at high temperature.

FIG. 2 shows an example of the structure of a silicon substrate using this semiconductor substrate. The silicon semiconductor epitaxial layer 4 is made of monosilane (SiH ₄ ), silicon tetrachloride (SiCl ₄ ) dichlorosilane (SiH ₂ Cl ₂ ), or the like. Raw gas, 9
By acting on the entire surface of the semiconductor substrate heated to 50 to 1250 ° C., it is formed in the thickness range of 0.3 to 20 μm. More specifically, for example, S is formed on the stabilized zirconia film 2 by an atmospheric pressure CVD method by thermal decomposition of SiH ₄ gas.
i heteroepitaxial growth is performed. The Si epitaxial growth is performed at a growth temperature of 950 to 1250 ° C. and a H ₂ flow rate of 1
A good single crystal growth film can be formed under the condition of 00 / min and SiH ₄ concentration of 0.1%.

As described above, the semiconductor substrate of the present invention forms a single crystal oxide film directly on a silicon substrate, and utilizes the fact that the single crystal stabilized zirconia film is an oxygen conductor at high temperature to stabilize the silicon substrate. By forming a SiO ₂ layer at the interface of the zirconia oxide film and combining the single crystal stabilized zirconia film and the SiO ₂ layer, the breakdown voltage characteristic, the interface characteristic and the like are improved. In addition, since the single crystal stabilized zirconia thin film is stable at high temperature, it does not cause a reduction reaction unlike the sapphire substrate to give pollution to the epitaxial growth layer. Furthermore, single-crystal stabilized zirconia is a cubic crystal like silicon and has a lattice constant of silicon (5.4
It is close to 3Å) and misfit dislocations are hard to be included in epitaxial silicon.

The present invention is not limited to silicon semiconductor devices
It goes without saying that it can be applied to compound semiconductor devices such as aAs and InP.

(G) Effect of the Invention According to the present invention, a semiconductor substrate in which an oxide single crystal film is formed on a silicon substrate is formed, and thereby a high-performance and inexpensive SOI substrate is provided.

[Brief description of drawings]

1 (a) to 1 (c) are explanatory views showing the manufacturing process and structure of one embodiment of the present invention, and FIG. 2 is an explanatory view showing an application example of this embodiment. (1) …… Silicon substrate, (2) …… Single crystal stabilized zirconia film, (3) …… SiO ₂ layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryokan Kakihara 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Fumihiro Atsushi 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation

Claims (1)

[Claims] 1. A silicon substrate, a stabilized zirconia single crystal film coated on the silicon substrate, and a silicon substrate coated with the stabilized zirconia single crystal film, which is heat-treated in an O ₂ atmosphere to obtain the silicon substrate. A semiconductor substrate comprising a SiO ₂ film formed between the stabilized zirconia single crystal films.