JPS5837972A - Amorphous silicon semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain an a-silicon semiconductor device comprising the N type a-silicon layer with excellent characteristic by forming the a-silicon layer containing the antimony in the specified rate. CONSTITUTION:A vacuum pump (a) is connected to the bell jar 1 through the exhaust path 3 having the butterfly valve 2 and is kept in a high vacuum condition. A substrate 4 is placed therein and is heated by the heater 5 and simultaneously a DC negative voltage is applied to this substrate 4 from the DC power supply 6. While the hydrogen is being supplied to the bell jar 1 from the hydrogen discharge tube 7, both silicon evaporation source 8 and antimony evaporation source 10 are heated and simultaneously evaporated, thereby forming the a-silicon to which the antomony and hydrogen are implanted is deposited on the substrate 4. The a-silicon layer 30 containing the antimony of 0.01- 10atom% is thus formed. A desirable semiconductor element can be formed on the layer 30.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an amorphous silicon semiconductor device and a method for manufacturing the same.

(2) In order for a general type of semiconductor material to be useful, it is necessary that it can be made arbitrarily Kn-type or p-type by doping, and in this respect, crystalline silicon is widely used in practical applications. It is not a moat in light of the fact that
Although crystalline silicon is an extremely useful semiconductor material, its production requires a great deal of time and cost (in addition, it is difficult to obtain a thin layer with a large area).

On the other hand, amorphous silicon C is hereinafter referred to as "a-silicon". ), it is very advantageous in that it does not require the process of crystal growth and can easily obtain a thin layer with a large area, but its irregular atomic arrangement structure, which is amorphous, makes it difficult to share Since there are many dangling bonds in the state where the bonds are broken, 11 has many gap states and cannot obtain a large doping efficiency, so its practical usefulness as a semiconductor material is extremely low. 0 This is because in order to obtain the required STP state, it is necessary to introduce an impurity element into a-silicon at an extremely high concentration, and when an impurity element is introduced at such a high concentration, 1- As a result of the structural state of silicon changing and crystallizing, the a-silicon has a low modulus of carriers (electrons or holes) normally generated by doping, and is highly unstable. This is because the matrix becomes sharp and stuck, making it impossible to obtain effective doping efficiency.

Against this background, the so-called glow discharge method has been known as a method for obtaining a-silicon useful as a semiconductor material. In this glow discharge method, silane gas is decomposed by glow discharge in a deep chamber to generate active silicon and hydrogen atoms or partially decomposed products, and dangling bonds are formed on the substrate provided in the vacuum chamber. In the method of depositing breath-silicon in a state blocked by hydrogen atoms, the doping is performed with a gas which is a hydride of an element of group II or group II of the periodic table, together with silane gas,
That is, this is carried out by introducing diporan, phosphine, arsine, etc. into the vacuum chamber.

According to this glow discharge method, the obtained a-silicon can be said to be a useful semiconductor material because the dangling bonds are blocked by hydrogen atoms.
In doping, it is necessary to use diborane, phosphine, arsine, etc. that can be decomposed by glow discharge along with silane gas, and these are toxic gases that are difficult to handle and cause pollution, so complete countermeasures must be taken. In addition, silane gas is also a dangerous gas with the potential to explode, so countermeasures are also required. Therefore, there are considerable obstacles to manufacturing silicon semiconductor devices using the glow discharge method on an industrial scale.

In addition, in the glow discharge method, the structural state of the obtained a-silicon and the i of the impurity element in the case of doping are
-Although the ratio of K introduced into silicon depends on the state of the plasma generated by glow discharge, it is extremely difficult to control the state of this plasma, and it is difficult to maintain it stably.(5) Therefore, it is not possible to sufficiently control the proportion of hydrogen introduced into a-silicon and the concentration of impurity elements, resulting in a desired state, for example, a conductivity type in which impurity elements are introduced at a high concentration. It is almost impossible to obtain a-silicon with good properties.

Furthermore, in the glow discharge method, the film formation rate is extremely small, on the order of several angstroms/second, and it is difficult to manufacture a thin layer of a-silicon over a large area with uniform thickness and homogeneity. It is very difficult to control the IG because it depends on the state of the plasma.

Although it is possible to carve useful a-silicon using the glow discharge method, it is still possible to manufacture tortoise-silicon semiconductor devices with desired characteristics advantageously on an industrial scale in practice. I'm glad I was able to do that.

In addition to the glow discharge properties described above, sputtering is also known, but it is necessary to use the same gas for doping as in the Kt1 glow discharge method (6), and the environmental conditions under which sputtering can be performed This method has the same or similar drawbacks as the glow discharge method, such as a limited degree of control freedom and a low film forming rate, as in the glow discharge method.

The present invention was developed based on the above circumstances, and is a 1-silicon semiconductor device having an 11-type 1-silicon layer and having excellent characteristics! The object of the present invention is to provide a method that can produce the same very advantageously.

The features of the present invention a-silicon semiconductor device are as follows:
a containing antimony in a proportion of 0.01 to 10 atoms a
- in that it has a silicon layer.

Invention 1 - A feature of the method for manufacturing a silicon semiconductor device is that in the presence of active hydrogen and hydrogen ions obtained by discharging hydrogen gas in a vacuum chamber, a silicon evaporation source is provided in the vacuum chamber. And heat the antimony evaporation source to mix silicon and antimony at 1:0.01~
evaporated simultaneously at an evaporation rate ratio of 1, and thus placed in the vacuum chamber. The method includes a step of forming an a-silicon layer containing antimony on a substrate.

The present invention will be specifically explained below with reference to the drawings.

In the present invention, as shown in FIG. 1, a vacuum pump 10 (shown in the figure) is connected via an exhaust path 3 having a Pelger IK butterfly valve 2 forming a vacuum chamber, and thereby the inside of the Pelger 1 is connected. For example, 101-10-machine err
The substrate 4 is placed in the Pel jar 1 and heated to a temperature of 150 to 500°C by the heater 5.
While heating preferably Fi to 250 to 450°C, the substrate 4 is heated to O to -10 KV, preferably tj by a DC 11 source 6.
-1 to -6 KV (D negative DC voltage is applied to the Pelger 1 to discharge active hydrogen and hydrogen ions from the hydrogen gas discharge tube 7 provided in the Pelger 1 with its outlet facing the substrate 4. The silicon evaporation source 8 and the antimony evaporation source 10 facing the substrate 4 are heated together while silicon and antimony are introduced into the substrate 4 so that the evaporation rate ratio of silicon and antimony is 1.
: evaporated at the same time at an evaporation rate of 0.01 to 1, and from this K, a-silicon into which antimony and hydrogen were introduced was deposited on the substrate 4, thereby forming a substrate as shown in FIG. 4, an a-silicon layer 30 containing antimony at a ratio of 0.01 to 10 atomic arcs is formed.
- forming a semiconductor element in the silicon layer 30 to manufacture a semiconductor device; aFi shutter for each evaporation source 8.10.

In the above, for heating the silicon evaporation source 8 and the antimony evaporation source 10, a heating means such as resistance heating, electron gun heating, induction heating, etc. can be used.

At each evaporation source, coarse grains fly off due to bumping, and the substrate 4
It is necessary to avoid the particles from adhering to the particles, and for this reason, a coarse particle scattering prevention member that forms a curved steam path can be used.

In addition, the evaporation rate of silicon and 7-timony must be reliably controlled by detecting the evaporation rate or deposition rate using a crystal monitor, quadrupole mass spectrometry analyzer, atomic absorption detector, etc. Can be done.

In one example of the hydrogen gas discharge tube 7, as shown in FIG. 3, one of the cylindrical tubes 1! A housing member 22 and one electrode member 22 were provided at one end. A discharge space member 24 made of, for example, cylindrical glass that surrounds the discharge space 23 and the other ring-shaped electrode member 26 having an outlet 25 provided at the other end of the discharge space member 24, Electrode member 22 and the other electrode member 2
By applying a direct current or alternating current voltage between 6 and 6, hydrogen gas supplied via gas supply 21 causes glue discharge in space 23, which is activated by electronic energy from K. Active hydrogen and ionized hydrogen ions, which are composed of water purple atoms or molecules, are discharged through the outlet 25. The discharge space member 24Fi in this illustrated example has a double pipe structure and has a #I configuration through which cooling water can flow.
7.28 shows the cooling water inlet and outlet. 29F! This is a cooling fin for one electrode member 22.

Electrode mass sale 5lFi10 for the above Konoha gas discharge tube 7
~15ffi tear b, applied voltage 11500~800V,
The pressure in the discharge space 23 is assumed to be approximately FilO-''mm.rr.The semiconductor device shown in FIG. 2 will be described later.

In the semiconductor device of the present invention, since the a-silicon layer contains antimony in an amount of 0.01 #+-% or more, the 1-silicon layer definitely has the performance as a K nm semiconductor, and also contains antimony. Since the ratio is less than tOW, there is no problem such as crystallization of 1-silicon as a matrix. The reason why such a doping effect is obtained due to antimony is, of course, the above 1.
- This is because silicon has its dangling bonds blocked by hydrogen atoms. However, if the antimony content is less than 1,000%, the doping effect cannot be reliably obtained in practice.

In addition, in the method of the present invention, silicon and antimony are deposited simultaneously in the presence of active hydrogen and hydrogen ions obtained by discharging hydrogen gas, and silicon and antimony are deposited at a ratio of 1:0.01.
Since the vapor deposition is carried out by evaporating at an evaporation rate ratio of ~1, the content ratio of antimony is 0.01 as described above.
An a-silicon layer of ~10 atoms can be reliably formed.

In the present invention, as mentioned above, the impurity substance used to obtain KII type a~silifune is antimony alone, so it is very easy to handle, and it is also free from danger and toxicity, including the silicon source. There is no need for special consideration for this, and there is no risk of it becoming a cause of pollution.

Furthermore, in the vapor deposition of the present invention, it is possible to independently control the evaporation rate of antimony, and as described above, the evaporation rate or deposition rate can be detected and controlled with high accuracy according to the result. In addition, it is possible to control the heating temperature and applied voltage of the substrate, the evaporation rate of silicon, and the amount of hydrogen gas supplied to the hydrogen gas discharge tube, the discharge voltage, etc. Since the degree and amount of activity of active hydrogen and the amount of hydrogen ions can be controlled independently, it is easy to form 1-silifone with a desired antimony content within the above range. Hitoshi and JP-A-58-37972 (4) obtain a semiconductor device using a type 1 a-silicon layer with good characteristics
) can be done.

Furthermore, it is easy to increase the deposition rate of a-silicon by several tens of times that of the glow discharge method. A square-shaped a-silicon layer that is uniform in direction, has a uniform antimony concentration distribution, and has a uniform thickness can be formed in a short time.

In the present invention, antimony vapor Kl of antimony evaporation @10! It is preferable to irradiate the particles, thereby increasing the adhesion efficiency of cyanantimony. To do this, for example, as shown in FIG. 4, K installs a thermoelectron generation heater 42 in an electron generation chamber 41 surrounded by a glass wall, and installs a glass electron guide tube 43 in the electron generation chamber 41. Using the connected electron supply device 40, the tip of the electron guide tube 43 may be inserted into the Pelger 1 and positioned near the antimony evaporation jllO. 44 is a power source connected to the heater 42, 45 and 46 are accelerating electrodes provided on the inner surface of the electron guide tube 43, and a source for the DC 1 (13). For such electron supply device 4o),
It is also effective to simply provide a single Kl ion emission heater near the antimony evaporation source 10.

Any semiconductor element can be formed on the a-silicon layer 30 by utilizing the fact that it is n-type or regardless of its conductivity. For example, in the example shown in the TF12 diagram, a so-called non-doped layer 31 is doped with impurities on the a-silicon layer 30, and the layer 31 on the non-doped N31 is made of a metal with a high work function such as platinum, gold, palladium, etc. A thin layer 32 is provided, and a transparent electrode film 33 called a K1-0 film is formed thereon.A solar cell is constructed using a metal substrate as the substrate 4.゛＼ It will be done. Furthermore, by forming the a-silica layer 30 with a high antimony content and a low resistance value, there is an ohmic relationship between the metal substrate or the metal layer provided on the surface of the insulating metal substrate. Since a contact can be formed, this can be used to construct, for example, a field effect transistor. When forming a semiconductor layer of 1-silicon on the silicon layer 30, the W! The silicon evaporation source 8 used to form the silicon layer 30 can be used as is, and when the antimony evaporation source 10 is not used, it is sufficient to close the shutter S without heating it. Of course, it is also possible to provide an evaporation source within the Pelger 1 and utilize it.

An embodiment of the present invention will be described below in the case of manufacturing a solar cell. In the apparatus having the configuration shown in FIG. A chromium layer with a thickness of about xoooi formed by sputtering was used as a substrate for vapor deposition, and this substrate was heated to a temperature of 450°C, and a DC noble voltage of 14 KV was applied to the metal support plate that supported the substrate. In this state, the silicon evaporation source and the antimony evaporation source were heated using a resistance heating method, and the evaporation state of silicon and antimony was monitored using a crystal monitor and a quadrupole mass spectrum analyzer to achieve an evaporation rate of 1:0.1. A layer of n-type a-silicon approximately 100 λ thick was formed on the chromium layer of the substrate for 3 seconds. During this time, the hydrogen gas discharge tube type has a flow rate of 100e5/
Hydrogen gas was supplied at a ratio of 12), and a DC voltage of 600 V12) was applied between both electrode members to generate glue discharge. The content ratio of antimony in the a-silicon layer obtained here was Fi2 atomic arc.

Next, while maintaining the hydrogen gas discharge tube in its operating state, only silicon was evaporated for 333 seconds to form a non-doped layer with a thickness of 1 J, and platinum was deposited on top of the non-doped layer with a thickness of 1 J.
Form a thin layer of platinum with a thickness of 50λ by evaporating for seconds,
Furthermore, a transparent electrode film mainly composed of indium oxide and having a thickness of 800 i was formed thereon to produce a solar cell. The conversion efficiency of this solar cell is an open voltage of 400 when exposed to light from Air Mass 2! The IIV% short circuit current was 5 A/sf.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view showing an example of a device used to carry out the method for manufacturing a semiconductor device of the present invention, and FIG. 2 is an explanatory sectional view showing the configuration of a solar cell which is an example of a semiconductor device manufactured by the method of the present invention. 3 is an explanatory sectional view showing the configuration of an example of a hydrogen gas discharge tube used in the present invention, and FIG. 4 is an explanatory sectional view showing an example of an electron supply device effectively used in carrying out the method of the present invention. FIG. l...Pelger 3...Exhaust path 4...Substrate 6...DC power source 7...Hydrogen gas discharge tube 8...Silicon evaporation source 10...Antimony evaporation source 21...Gas inlet 22.26... Electrode member 23... Discharge space 30... Amorphous silicon layer 31... Non-doped layer 33... Transparent electrode film 40-... Electron supplier first
Figure 2 Figure 3 Figure 4 Procedural amendment (1 button July 2, 1980 Director of the Japan Patent Office Kazuo Wakasugi 1 Display of 11 cases Showa 1966 Patent Application No. 135591 2 Name of the invention Amorphous silicon Tei conductor packaging W and its manufacturing method 3, Relationship with the amended person case Patent applicant ``'° Shin 2J@M, 1-26 Nishi-Shinjuku, Shinjuku-ku, Tokyo
l ++ ;, name) (127) Roku Konishi Photo Industry Co., Ltd. 4 Agent 6 Number of inventions increased by amendment 7 Detailed explanation of the invention in the specification subject to amendment: '18
Contents of amendment 1) Specification @ page S, line 3: “Jt- that changes and crystallizes”
2) On page 3, lines 9 to 11 are corrected as follows. [Therefore, when h-silicon is used as a material for semiconductor devices such as solar cells or field effect transistors, there are many more problems to be solved than when using crystalline silicon. For example, as mentioned above, in a-silicon, there are many gap units caused by dangling bonds within its energy gap, so that the a-silicon cannot be used to form a semiconductor layer of a semiconductor device until the energy gap is formed. However, it is known that it is possible to uniformly change the properties of this fil condyle by introducing hydrogen atoms into the a-silicon to block the dangling bonds. *- When controlling the conductivity type of silicon, doping to obtain the desired conductivity type is not as easy as crystalline silicon, and it is difficult to obtain a good l-type or #'ip-type semiconductor by doping. The type and amount of dopant suitable for obtaining an n-type 1-silicon semiconductor on an industrial scale has not yet been found, and for this reason, it is difficult to use it as a semiconductor layer of a semiconductor device. Practically desirable! Type I a-silicon semiconductors NF1 have not been obtained in yl and ferro. Regarding the method of manufacturing an n-type 1-silicon semiconductor layer,
The glow discharge method is known as one of the conventional methods. 3) Lines 18 and 19 of page 1!3 of the same book are corrected as follows. "Gases that are hydrides of elements in group II of the periodic table, namely phosphine and arsine" 4) Same #! Delete "diborane," in line 7 of page 4. 5) Lines 11 and 12 of page 6 are corrected as follows. [The point here is that antimony is selected as the dopant, and the a-silicon layer contains antimony in a doping amount of 0.01 to 10,000, which is different from that in the case of crystalline silicon. ”6) Same #! Correct the 20th line on page 6 to read "low manure". 7) "Hydrogen gas" in page 6, no line 14 of the same page is replaced with "hydrogen gas, not just hydrogen gas.""Gas," he corrected.

Claims (1)

Claims: An amorphous silicon semiconductor device comprising an amorphous silicon layer containing 0.01 to 10 atoms of antimony. 2) In a vacuum chamber, silicon and antimony are heated by heating hydrogen gas to tK. A method for manufacturing an amorphous silicon semiconductor device, comprising the step of simultaneously evaporating at an evaporation rate ratio of O2N2, thereby forming an amorphous silicon layer containing antimony on a substrate placed in the vacuum chamber.