JPH01155659A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To improve an hFE and to achieve a high current amplification factor in a HBT by a method wherein a divergent magnetic field type electronic cyclotron resonance unit is used, and by an ECR plasma vapor growth method, beta-SiC is epitaxially grown on an Si4 deg.-off substrate doped with N-type ions. CONSTITUTION:On an Si(111)4 deg.-off substrate 31 placed in a plasma reaction chamber 12 in a divergent magnetic field type electronic cyclotron resonance unit heated to 400-500 deg.C, silicon carbide is grown, which is accomplished by introducing Si2H6 gas or Si3H8 gas into the plasma reaction chamber 12 and C2H2 gas, C2H4 gas, or C3H8 gas into a plasma generating chamber 11, the latter together with hydrogen or helium. With beta-SiC being formed in this way, an HBT emitter may be built at a low temperature, a high-concentration base region 33 is prevented from re-diffusion, while a base junction and an emitter 34 may be formed on a shallow base region 33.

Description

[Detailed Description of the Invention] [Summary] Silicon carbide (SiC) is grown on a semiconductor (silicon) substrate at low temperature to produce a heterojunction bipolar transistor (Heterojunction bipolar transistor).
erojunction Bipolar Trans
istorp, HBT) on a semiconductor (silicon) substrate at a lower temperature than conventional methods.
The purpose of the present invention is to provide a method for forming IBTs using a divergent magnetic field type electron cyclotron resonance plasma vapor phase epitaxy apparatus.
Si
, H, or 5iJs gas into the plasma reaction chamber, C,
The present invention includes a method for manufacturing a semiconductor device, characterized in that H, C2H, or C3IJ gas is introduced into a plasma generation chamber together with hydrogen or helium to grow silicon carbide (SiC) on the substrate.

[Industrial Application Field] The present invention provides silicon carbide (Si) on a semiconductor (silicon) substrate.
C) is grown at low temperature to form a Heterojunction Bipolar transistor.
Transistor, HBT).

[Conventional technology]

The conventional method uses a combination of 5i) lcl, C, H, and gases under reduced pressure (approximately 200 Pa) and at a high flow rate (50
cm/sec or more), flow rate ratio (C3H8/5i)Ic
I! , 3) Range of 0.01 to 0.5, growth temperature 900
~1100°C (typically 1000°C), (111)
It grows SiC on a silicon substrate, and more specifically, referring to Figure 3, it grows SiC on a silicon substrate (wafer).
A reactor (quartz tube) 43 heated by an RF coil 44 mounted with 41 is evacuated using a booster, a pump 45 and a rotary pump 46, and the above-mentioned growth gas and carrier gas (H2) are passed through a mass flow roller 47. The SiC crystal is grown on the wafer 41 by supplying the SiC crystal. In the figure, 48 is an oscillator, and 49 is a vaporization controller.

[Problem that the invention seeks to solve]

When attempting to form an HBT as a practical example of the above method, the growth temperature is high as described above, so re-diffusion of impurities occurs in the base region, resulting in a shallow
) It becomes difficult to form the base region), making it difficult to take full advantage of the advantages of IBT (current amplification factor (hr)).Also, the reaction environment is under reduced pressure (several T).

rr), there is also the problem of incorporating other impurities such as NO.

Therefore, an object of the present invention is to provide a method of growing SiC on a semiconductor (silicon) substrate at a lower temperature than conventional methods and using the same to form an HBT with improved hFc.

[Means for solving problems]

The above problem was solved by using a diverging magnetic field type electron cyclotron resonance plasma vapor phase epitaxy apparatus and using a 5iJ6 Or 5iJ
A semiconductor device characterized in that silicon carbide (SiC) is grown on the substrate by introducing s gas into a plasma reaction chamber, C2H2, C2H4, or C, H gas, together with hydrogen or helium, into a plasma generation chamber. The problem is solved by the manufacturing method.

[Function] In the above method, β-5iC is formed at low temperature, so
The HBT emitter can be made at a low temperature, preventing re-diffusion of a highly doped base region, and making it possible to form an emitter and base junction in a shallow base region.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to illustrated embodiments.

In the present invention, a divergent magnetic field type electron cyclotron resonance (ECR) device is used, and the ECR plasma vapor phase epitaxy (CV
N-type ion-doped silicon (111
) Epitaxially grow β-5iC on a 4'off (OFF) substrate.

FIG. 1 is a schematic diagram of a divergent magnetic field type ECR plasma CVD apparatus.

This ECR-CVD apparatus includes a plasma generation chamber 11 and a plasma reaction chamber 12. Microwaves with a frequency of 2.45 GHz generated by a microwave oscillator 13 are introduced into the ECR plasma generation chamber 11 through a rectangular waveguide 14. A magnetic coil 1 is installed around the plasma generation chamber 11.
5 is arranged to satisfy ECR conditions within the plasma generation chamber 11. In addition, the exhaust configuration uses turbo molecular compound pumps (T, M,
P, ) 16 (Exhaust 'J; 18001 /5ec)
, mechanical booster pump (M, B, P,) 17
(Roots pump) is used to exhaust the air. In FIG. 1, 18 is a plasma shutter, 19 is a sample, 20 is a heater, and 21 is a rotary pump (R, P,).
, 22 indicate matching 6 boxes.

In carrying out the present invention, the above-mentioned substrate is
Heat to 0° C. for several seconds to several minutes) and remove the natural oxide film on the substrate surface using ECRHz gas plasma (substrate cleaning).

After basic cleaning, add H2 or H2 to the plasma generation chamber.
Introducing e and CzHz, C2H, or C, +1 Il,
Si, H6 or 5izHa is introduced into the reaction chamber. Or helium (He) in the plasma generation chamber 11, 5izHb or 5I3H8 in the plasma reaction chamber 12, and C,
Introduce H2, CzH, or CJs/H2 or) Ie. The substrate temperature at that time is 400-500"C
Make it. As the dopant gas, B2H5 is used for P type and Plh is used for N type, as in the case of doping a silicon substrate. The temperature conditions for the substrate described above are conditions that have been confirmed to be optimal through experiments.

To form an HBT using the above method, referring to FIG.
32P+ type region (base region) 33 is formed and then β-
When the 5iC emitter 34 is formed by the method described above, 4iC emitter 34 is formed by the above method.
Since impurity diffusion in the base region 33 does not occur at a temperature of 00 to 500 degrees Celsius, the vertical and horizontal expansion of the shallowly formed base region 33 is prevented, and the advantages of I (BT) are utilized, and according to experiments, hFE It was possible to take a value of 800 to 1000. In Figure 2, 35 is a 5iOz film;
36, 37, and 38 are a polysilicon base electrode, emitter electrode, and collector electrode, respectively. Alternatively, instead of the above method, a P+ type region (23) may be formed in the N0 type region 22 grown by ECR epitaxial growth.

[Effects of the Invention] As described above, according to the present invention, an emitter-base junction using β-3iC is formed in a shallow base region with a wide gap of 2.2 eV, and a high base concentration can be maintained. This improves hFE in HBT and is effective in obtaining a high current amplification factor of 1 (BT).

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a divergent magnetic field type ECR plasma CVD apparatus, Fig. 2 is a cross-sectional view of a 1 (BT) with β-5iC as an emitter, and Fig. 3 is a layout diagram of a conventional SiC film growth apparatus. 1 and 2, 11 is a plasma generation chamber, 12 is a plasma reaction chamber, 13 is a microwave oscillator, 14 is a rectangular waveguide, 15 is a magnetic coil, 16 is T, M, P. 17 is M, B, P. 18 is a plasma shutter, 19 is a sample, 20 is a heater, 21 is R, P. 32 is an N3 type region, 33 is a base region, 34 is an emitter, 35 is a Sin, film, 36 is a base electrode, 37 indicates the emitter electrode, and 3 indicates the collector electrode. Patent applicant: Fujitsu Limited

Claims (2)

[Claims] (1) Using a divergent magnetic field type electron cycloton resonance plasma vapor phase epitaxy apparatus, on a silicon (111) 4° off substrate heated to 400°C to 500°C and placed in the plasma reaction chamber (12), Si_2H_6 or Si_3H_8 gas is transferred to plasma reaction chamber C_2H_2, C_2H_4 or C_3H8.
_ gas is introduced into a plasma generation chamber together with hydrogen or helium, and silicon carbide (SiC) is grown on the substrate. (2) Base region (33) in N^+ type region (32) formed on N-type silicon (111) 4° off substrate (31)
is formed and the SiC emitter (34) is connected to the base region (33).
) and making contact with the base region; and an emitter electrode (37) in contact with the emitter (34).
), forming a collector electrode 38 in contact with the N^+ region (32).
The method described in section.