JPS6084824A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To enable composition of high-resistance SiC as an insulating film or a protective film and to prevent generation of a crystal defect by thermal expansion coefficient of that and further to enable thickening of the film by implanting BeO, BN or the like in the SiC formed in advance by ion implantation method. CONSTITUTION:A low-resistance SiC polycrystalline film 2a formed on a main surface of an Si single crystal substrate 1 by ion implantation is doped with BeO so as to make the film insulating, i.e. high-resistance. For the ion implantation, a solid source of BeO as an ion source is used or a solid surce of Be and a gas source of O are used together to perform a heat treatment. Next, after the SiC film 2 is selectively removed by etching, impurity such as arsenic is doped in the main surface of the exposed Si substrate 1 to form a buried layer 3, on which an epitaxial layer 4 is formed and n and p type impurities are selectively diffused. As thermal expansion coefficients of the high-resistance SiC film 2 and the Si substrate 1 are equal, stress is not generated in the Si single crystal even if the SiC films 2 and 6 are formed to be thick.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an insulating film and an insulation film. ! The present invention relates to a method of manufacturing a semiconductor device that can improve characteristics by using an electrically insulating silicon carbide film.

[Background technology]

In a semiconductor device in which circuit elements are formed on the main surface of a semiconductor substrate such as silicon, an isolation film that provides insulation between the elements, an interlayer insulation film that provides insulation between upper and lower layers, and furthermore, A variety of membranes are required, such as a vacuum membrane and a sociation membrane, to trap water from outside air and moisture. Conventionally, a silicon oxide film (Sin film) has been used as the moderate σ film. The 5in2 film has a different coefficient of thermal expansion than silicon and has a large volumetric expansion, so it often grows inside the silicon substrate (
This causes stress in the single crystal (within the single crystal) and causes crystal defects. For this reason, it is not preferable to form a thick SiO film (SiO, which is thin and has a problem in that the interconnect capacitance increases due to K and hinders the high speed of the device. Also, crystal defects There is also a problem in that the occurrence of σ) impedes the miniaturization of elements, that is, higher integration.

Q) Because of this, the inventor &! We investigated various materials to replace SiO and films, and focused on silicon carbide (SiC) as one of them. That is, JP-A-56-
As described in No. 66086 and No. 57-2591, SiC, which contains many impurities such as beryllium oxide (Bed) and boron nitride (BN), has high resistance as an insulator and has a thermal expansion coefficient similar to that of silicon. Moreover, it has extremely high thermal conductivity, and it is thought that if it is used in the above-mentioned insulating film or protective film, the above-mentioned problems such as preventing the occurrence of crystal defects can be solved. However, since this electrically insulating SiC is obtained as a sintered body made by hot-pressing powder material, it is virtually impossible to form it on a semiconductor substrate, and it is difficult to realize a solution to the problem. It is difficult.

In addition, monosilane (SiH4) and propane (CsHa)
At the 41st Annual Meeting of the Japan Society of Applied Physics, SiC films are formed on silicon substrates using chemical reactions to form light-emitting devices, etc.
However, this SiC is a semiconductor, that is, a low resistance material, and cannot be used as an insulating film.

[Purpose of the invention]

The purpose of the present invention is to enable the formation of an electrically insulating SiC film as an insulating film, a protective film, etc. of a semiconductor device, thereby preventing the occurrence of crystal defects, etc., and improving characteristics as well as increasing speed and integration. An object of the present invention is to provide a method for manufacturing a semiconductor device that can achieve the following.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

In other words, it is made to have high resistance by incorporating previously formed SiC [BeO+BN etc. by ion implantation method etc., and this makes it possible to make electrically insulating (high resistance) SiC into an insulating film or a protective film. Its thermal expansion coefficient prevents the occurrence of crystal defects and makes it possible to increase the thickness of the film.
O that can achieve high integration [Embodiment] i (see Figure 1) to 0 show embodiments in which the present invention is applied to bipolar transistors in the order of their manufacturing steps.

First, as shown in Fig. 6), the (i o o) plane is 20 in P type.
A high resistance SiC film 2 is formed to an appropriate thickness on the main surface of a silicon (Si) single crystal substrate 1 having a resistivity of ~50 Ω. This 5iCf1%2 contains 5iCVcBeO as an impurity, has an electrical resistivity of 1d0Ω, has a high resistance on the drawing board, and is almost an insulator, and has a thermal expansion coefficient of 3X10.
Thermal expansion coefficient of silicon substrate l at around 1°C is 2 to 3 x 101
Almost equal to °C. Furthermore, the thermal conductivity kt O,5Cai/
e=s・S・℃, which is equivalent to or higher than that of metals.

The SAC film 2 is formed by a chemical vapor deposition method using a chemical reaction and an ion implantation method.
5in2. Cf1. , , 5iHC et al. Nosilancast CH, , C, ■I6. Hydrogenated carbon gas such as C, 8, C, H, etc. is used as the main reaction gas, 11. , He etc.σ
) A chemical reaction is caused on the silicon substrate 1 heated to a predetermined temperature while flowing a carrier gas, and a SiC polycrystalline film 2a is deposited.

The heating temperature varies depending on the type of gas mixture, but ranges from several hundred degrees to about 100 degrees Fahrenheit. BeO is added by ion implantation to the thus formed polycrystalline film 2a having semiconductor characteristics, that is, low resistance, σls+c, to insulate it, that is, to make it high in resistance. As for the ion implantation method, BeO is directly implanted using a solid BeO source as an ion source, or a solid Be source and an O gas source are used together, and then the ion implantation is performed at temperatures ranging from several hundred degrees to fawn temperature. There is a method of forming BeO by heat treatment.

Next, after selectively etching away the SiC film 2 as shown in FIG.
form. Thereafter, epitaxial growth is performed to form an n-type epitaxial layer 4 as shown in FIG. 1cI.

Next, the main surface of this epitaxial layer 4 is coated with n by a conventional method.
By selectively diffusing type and p-type impurities, the same figure (as shown in D, epitaxial layer 4 is used as collector C)
A bipolar transistor QB can be constructed in which the p-type layer serves as the base B and the n+ layer serves as the emitter E. Reference numeral 5 designates a contact V contact, and reference numeral 6 designates a high-resistance SiC film formed by Sing deposition and BeO ion implantation in the same manner as described above, and is configured as an interlayer insulating film. 7 is AJ configuration g.

According to the semiconductor device constructed in this manner, the coefficient of thermal expansion of the high-resistance SiC film 2 is almost equal to the coefficient of thermal expansion of the silicon substrate 1, as described above.

Even if SiCPMs 2 and 6 are formed thickly, no stress is generated in the silicon single crystal, and no crystal defects are generated. As a result, since there are no crystal defects, it is possible to miniaturize the device, that is, to increase its integration, and since it can be formed into a thick film, the wiring capacitance can be reduced and the speed of the device can be increased. Furthermore, since the thermal conductivity is high, there is also the advantage that the element surface σ) heat dissipation can be improved.

[Embodiment 2] FIGS. 2(5) to 2D show an embodiment in which the present invention is applied to an MO8 type field effect transistor in the order of its manufacturing steps.

First, as shown in the figure, it is (100) plane, p type, 1~5Ω,
Sin, film 12 on the surface of the silicon substrate 11 of the resistivity of the foil
After forming and patterning it into a predetermined shape, the surface of the silicon substrate 110 is selectively etched using this Sin film 12 as a mask to form a recess 13 as shown in FIG.

Next, as shown in FIG. 1c), a high-resistance SiC film 14 is deposited on the entire surface to a thickness sufficient to fill the recess 13, and then the SiC film 14 formed in a convex shape outside is selectively etched. According to the same figure (like the DJ), it is constructed on a substrate using SiC 14 as an inter-element isolation insulating film.

The SiC film 14 is formed by forming a SiC polycrystalline film (low resistance) as in the previous example, and then directly implanting BN using a solid source of BN as an ion source, or by implanting a solid source of B and a solid source of N. Ion implantation is performed using a gas source, and then heat treatment is performed to form BN. This SiC film 141C also has high resistance as an insulator and a coefficient of thermal expansion equal to that of silicon.

They also have high thermal conductivity.

Next, as shown in Figure C), after forming the rcsiO film 15 as a gate insulating film, a polysilicon gate film 16,
Source layer 17 formed by ion implantation of N-type impurities into the substrate
．． By forming the drain layers 18, an MO8 type field effect transistor can be formed. In the figure, 19 is PF
Glabella insulating film such as 3G.

20 is an All wiring.

In this example as well, since the insulating film for isolation between elements is formed of electrically insulating 5iCIIL, its thermal expansion coefficient is equal to that of the silicon substrate, preventing the occurrence of crystal defects and achieving high integration of elements. On the other hand, since it can be formed into a thick film, wiring capacitance can be reduced and high speed can be achieved. Moreover, it goes without saying that the heat dissipation effect can be improved by the high thermal conductivity.

As shown in FIG. 3, when using a SiC semiconductor substrate, an insulating film can be integrally formed on the substrate by selectively incorporating BeO+BN into the main surface of the SiC substrate by ion implantation. You can also do it. Also, ρtp m 4rIbh a on the main surface KBeO+C+BN of the 8i substrate
r −1”r I J−) L l# F / m f
iAh, #tk anti-SiC may be formed.

〔effect〕

(1) Low resistance (semiconductor) Si (C) is made to contain BeO+BN by ion implantation method or the like to increase resistance, so it can be easily formed into a finely patterned R film or a protective film.

(Since the high-resistance SIC film formed in 21 has a coefficient of thermal expansion equal to that of silicon, stress caused by the SiC film will not occur in the silicon crystal due to thermal changes, preventing crystal defects and improving the device performance.) Improved characteristics and higher integration can be achieved.

(335iCI [crystal due to rc] Since there are no defects, SiC
It becomes possible to form a thick film, reduce wiring capacitance, and achieve higher speed of the element.

Although the invention made by the present inventor has been specifically described above based on examples, it goes without saying that the present invention is not limited to the above-mentioned examples, and can be modified in various ways without departing from the gist thereof. Nor. For example, high resistance Si
C can be formed in the same way even when used as a tsipation film or a dielectric of a capacitor.

[Application field]

The above explanation mainly describes the case where the invention made by the present inventor is applied to transistors, which is the background field of application, but is not limited to this (ICs, LSIs, diodes, etc.). Similarly, for the rectifying element for high power, Fig. 1 (5) to ρ) are cross-sectional views showing the first embodiment of the present invention in the order of manufacturing steps, and Fig. 2 4 to ρ) are cross-sectional views of the manufacturing process of the second embodiment. It is a diagram.

1... Silicon substrate, 2... High resistance 5iCJli,
3... Buried layer, 4... Epitaxial layer, 6...
High resistance SiC film・11...Silicon substrate, 12...
8i0. film, 16... game), 17... source layer,
1g...Drain layer, 19...PSG film.

Agent: Patent Attorney Akio Takahashi heavenly sound ＼－＼J To To To Q

Claims (1)

[Claims] 1. A method for manufacturing a semiconductor device, which comprises adding BeO or BN to silicon carbide to form an electrically insulating P3m film of silicon carbide. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the addition of BeO is performed by ion implantation of Beα or Be and O. 3. The method of manufacturing a semiconductor device according to claim 1, wherein the addition of BN is performed by ion implantation of BN or B and N. 4. The method of manufacturing a semiconductor device according to claim 1, wherein silicon carbide is formed by a chemical reaction of silane gas and hydrogen gas.