JPS62119939A - Insulating substrate for semiconductor - Google Patents

Abstract

PURPOSE:To facilitate the handling of an Si substrate and to obtain an insulating substrate for semiconductor with good reproducibility by providing a thin oxide single crystal film on the Si substrate through a thin single crystal AlN film. CONSTITUTION:A thin AlN single crystal film 2 having a thickness of 10Angstrom -1mum is adhered on an Si substrate 1 by sputtering and so on for obtaining a highly insulative thin film to withstand a high temperature. A film of stabilized zirconia or the like is formed on this in a thickness of 0.1-10mum or thereabouts by a sputtering method and so on. Since the AlN film can be formed in an O2-free atmosphere, the oxide film 3 to be formed after that can be epitaxially grown without oxidizing the surface of the substrate 1. As the stabilized zirconia (ZrO2.Y2O3) film can withstand a high temperature, is stable to active H as well and its lattice mismatching with the Si substrate is also small, an SOI substrate having little defect can be formed in high purity.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to improvements in insulating substrates for semiconductors.

<Prior Art> Conventionally, insulating substrates for semiconductors have been manufactured by forming an oxide single crystal thin film on a silicon substrate.

However, with silicon substrates, the surface of the substrate is easily oxidized, resulting in the formation of a natural oxide film, so it is necessary to pay sufficient attention to the surface treatment and management of the substrate.

<Problems to be solved by the invention> When producing an insulating substrate for semiconductors by epitaxially growing an oxide single crystal insulating film on a silicon substrate, a natural oxide film (S-ioa) is always attached to the upper surface of the silicon substrate. The reality is that before forming an oxide insulating film, the substrate must be heat treated and sufficient care must be taken to manage the substrate surface, which is causing a significant deterioration of the natural ability of the substrate. . The present invention was devised in view of the above points, and aims to provide an insulating substrate for semiconductors having a structure that eliminates the above drawbacks, facilitates handling of the substrate, and improves reproducibility. This is what I did.

Means for Solving the Problems In order to achieve the above object, an insulating substrate for a semiconductor according to the present invention includes a single crystal thin film of aluminum nitride in which nitride is epitaxially grown on a silicon substrate. The structure is such that an oxide single crystal thin film is provided thereon.

<Function> The structure of the insulating substrate for a semiconductor according to the present invention is such that a single crystal thin film of aluminum nitride is formed on a silicon substrate as described above, and a single crystal thin film of oxide is further formed on the thin film of aluminum nitride. There is.

When a thin film of aluminum nitride is formed on a silicon substrate, it can easily grow as a single crystal, and a high-quality thin film can be obtained. Furthermore, when a thin oxide film is formed on top of the oxide, the interface is in contact between the nitride and the oxide, so that it does not come into direct contact with the surface of the silicon substrate and the influence of oxygen is removed. Therefore, in growing a single crystal of oxide, it is possible to significantly improve reproducibility compared to the conventional relationship between silicon and oxide.

In particular, as an oxide single crystal film, stabilized zirconia (Zr(h・Y2O3)
) and spinel (MgO11At303)
By forming the structure, a highly pure semiconductor epitaxial layer without autodoping of impurities can be obtained.

Therefore, by applying the insulating substrate having the structure of the present invention to a semiconductor device made of silicon or the like, it becomes easy to separate elements, and it becomes latch-up free.
It becomes possible to create VLSI such as CMOS.

<Example> Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a structural sectional view schematically showing the basic structure of an insulating substrate for a semiconductor according to the present invention.

In FIG. 1, 1 is a silicon substrate, on which a single crystal thin film 2 of aluminum nitride is provided, and on the single crystal thin film 2 of aluminum nitride, an oxide single crystal thin film 3 is formed. has been done.

The aluminum nitride single crystal thin film 2 is formed on the silicon substrate 1 by sputtering or MOCVD.

The film is deposited to a thickness of IOA to 1 μm by ALE, plasma CVD, ion plating method, or the like.

This aluminum nitride single crystal thin film 2 can withstand high temperatures and is easy to obtain as a highly pure thin film. Therefore, a high quality single crystal thin film with high insulation properties is produced.

Next, stabilized zirconia is formed on the aluminum nitride single crystal thin film 2 as an oxide single crystal thin film 3.

Sputtering and MOCVD films of spinel, etc.

It is formed by ALE, plasma CVD, ion plating method, etc. to a film thickness in the range of 0.1 μm to 10 μm.

The aluminum nitride single crystal thin film 2 on the silicon substrate 1 is
Since it can be formed in an oxygen-free atmosphere, the subsequent oxide film 3 (stabilized zirconia, spinel, etc.) can be epitaxially grown without oxidizing the surface of the substrate 1.

Stabilized zirconia (ZrO2/Y2O3) and spinel (MgO/At203) can withstand high temperatures, are stable against active hydrogen, and have small lattice mismatch with silicon, making them highly pure and defect-free SOI substrates. can be formed.

Next, the manufacturing process of a silicon semiconductor using the insulating substrate for semiconductor according to the present invention will be explained with reference to FIG.

In FIG. 2, reference numeral 11 denotes an insulating substrate for semiconductors according to the present invention, in which a semiconductor epitaxial film 12 made of silicon or the like is coated with monosilane (SiH4), silicon tetrachloride (SiCl2), SiHCl2
), using raw material gas such as disilane (SizHs),
Heating the substrate temperature to 950℃~1200℃, 0.3~
It is formed to a thickness within the range of 20 μm. The formed epitaxial film 12 has few crystal defects and exhibits good electrical characteristics.

Note that the present invention is applicable not only to silicon semiconductor devices but also to G
Needless to say, it can also be applied to compound semiconductors such as aAs and InP.

<Effects of the Invention> As described above, according to the present invention, an insulating substrate for a semiconductor in which a high-quality single crystal oxide film is formed on a silicon substrate is constructed, and thereby the performance of the semiconductor device is not adversely affected. It is possible to provide an SOI substrate that does not

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the substrate structure of an insulating substrate for semiconductors according to the present invention, and FIG.
FIG. 3 is a diagram showing a cross section of an I-substrate. DESCRIPTION OF SYMBOLS 1...Silicon substrate, 2...Single crystal thin film of aluminum nitride, 3...Single crystal thin film of oxide, 11...Insulating substrate for semiconductor, 12...Silicon epitaxial film. Agent Patent Attorney Aihiko Fuku (and 2 others) 2nd @

Claims (1)

[Claims] 1. An insulating substrate for a semiconductor, characterized in that a single crystal thin film of aluminum nitride is formed on a silicon substrate, and a single crystal thin film of oxide is formed on the aluminum nitride single crystal thin film. .