JPS6281765A - Method for manufacturing silicon carbide devices on silicon substrate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a silicon carbide (SiC) device capable of high-temperature operation, and particularly to a method for manufacturing a silicon carbide (SiC) device that is capable of high-temperature operation, and in particular, an SiC device using SiC grown on a silicon (Si) substrate. Relating to a manufacturing method.

[Conventional technology] SiC is a semiconductor that can operate at high temperatures.

The technology for growing SiC on a Si substrate has developed rapidly in recent years. For example, SiC can be grown on a (100) Si substrate by chemical vapor deposition using 5iHa and Z38B.
It has become possible to grow iopm. However, S
There were inconveniences such as the difference in thermal expansion coefficient between the i-substrate and SiC and the necessity of using a SiC thin slice obtained by melting the lattice Si substrate.

In addition, 5i0 obtained by oxidizing the SiC surface as an insulating layer
When using two films, the oxidation rate of SiC is very slow compared to Si, and it is difficult to obtain a 5i02 film of sufficient thickness.
The drawback was that it was difficult to manufacture transistors (MOS) and other devices.

[Problems to be Solved by the Invention] The present invention prevents the occurrence of cracks that are likely to occur in SiC grown on such a Si substrate, and also improves the insulation of wiring necessary for electrical property evaluation and device fabrication. A silicon carbide layer is grown on the insulating substrate required for device isolation, and a portion of the silicon carbide layer is removed to expose the surface of the silicon substrate, and the surface of the remaining silicon carbide layer and The method is characterized in that a silicon oxide film is formed on the exposed surface of the silicon substrate, and the silicon oxide film on the silicon substrate is used as an insulating layer for wiring of a device to be formed on the remaining silicon carbide layer.

[Function] According to the present invention, good self-alignment insulation can be ensured on the Si substrate.

0.5g of Si0 layer 20 was deposited by chemical vapor deposition method.
The film is grown to a thickness of about 1.0 m (Fig. 1(A)).

Next, a photoresist mask is provided on the SiC layer,
Plasma etching using freon and oxygen is performed to remove the SiC layer leaving SiC islands of the required shape and number (FIG. 1(B)); only one island is shown in the figure for convenience.

Next, it was heated at 1150°C for about 30 minutes in a steam atmosphere.

Thermal oxidation is performed (FIG. 1(C)), and the thickness of the 5i02 film 11 formed by this oxidation is approximately 0.0 mm on SiC 20.
05gm, but on Si 10 it is about 10 times that
．． Reaching 55 pLm.

SiC devices provided with transistors, integrated circuits, etc. can be easily manufactured.

A MOS with an n-layer of SiC provided on a Si substrate in this way
An example of manufacturing an FET will be described with reference to FIGS. 2(A) to 2(E). Using the SiC shown in FIG.
For example, it is removed by etching using a (NH4F +HF) solution (FIG. 2(A)).

A polycrystalline Si layer 3o is grown to a thickness of about 0.5 μm on the exposed SiC and Si02 on the Si substrate by, for example, chemical vapor deposition using thermal decomposition of SiH4 (see Fig. 2(B)). )) At this time, the polycrystalline Si layer 30 contains SiC.
An impurity serving as an acceptor, for example, AfL, is added to 20.

Next, in order to use the polycrystalline Si layer 30 as a source and drain electrode, the portion of the polycrystalline Si layer 30 corresponding to the gate electrode and other unnecessary portions are removed (see Fig. 2).
1 1IC)), the removal of polycrystalline Si is carried out using, for example, hot water as a corrosive agent, forming a 5i02 film 31 (Fig. 2(D)),
The thickness of the formed Si02 film 31 is that of polycrystalline Si30
It is about 0.5 grn on SiC20 and about 400 grn on SiC20.

The impurities previously added to the polycrystalline Si 30 are diffused into the SiC during this thermal oxidation to form source and drain regions @51 and 52. The thin part of the 5i02 film 31 above the SiC 20 is used as a gate insulating film, and the thick part above the polycrystalline Si 30 is used as an insulating layer for an electrode such as a gate metal that will be formed later.

C on the 5i02 film 31 on top of the polycrystalline 5i30.
F.

Plasma etching using (NH4F +H
F) The source electrode 41 (43) and the drain electrode 43 (43) are completely removed by wet etching using a liquid.
1), P-channel MO3FET as gate electrode 42
is completed (Figure 2 (E)).

On the other hand, in the step of forming the 5i07 film 31 (FIG. 2 (0)), if the insulating film is formed at a low temperature of 1000°C or less, the impurity added to the polycrystalline 5130 will be
There is almost no diffusion into the interior, rather polycrystalline Si 30 is Si
Since it exhibits ohmic contact with C, an n-channel MOSFET can be formed through the series of manufacturing steps described above.

Although FIG. 2 shows an example in which a P-channel and 09FET are formed on SiC grown on an S1 substrate, the SiC device of the present invention is not limited to this example.

[Effect of the invention] As explained above, -Si grown on a Si substrate
After removing part of C by etching

[Brief explanation of drawings]

1(A) to C) are partial cross-sectional views explaining the present invention in detail, and FIG. 2(A) to E) are MOSFEs using the present invention.
It is a partial sectional view showing an example of creating T. 10...Si substrate, 11, 31...5102. 20...SiC, 30...Polycrystalline S1. 41... Source (drain) electrode, 42... Gate electrode, 43... Drain (source) electrode, 51... Source (drain), Fig. 1

Claims (1)

[Claims] In a silicon substrate on which a silicon carbide layer has been grown, a portion of the grown silicon carbide layer is removed to expose the surface of the silicon substrate, and the surface of the remaining silicon carbide layer and A silicon oxide film is formed on the exposed surface of the silicon substrate, and the silicon oxide film on the silicon substrate is used as an insulating layer for wiring of a device to be formed on the remaining silicon carbide layer. A method for manufacturing silicon carbide devices on a silicon substrate.