JPS5935423A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a device having a P-i-N junction by a method wherein a molecular sieve or zeolite with an effective diameter in a predetermined range is utilized to adsorb and remove oxide gas or carbide gas with a molecular diameter not larger than 4.5Angstrom , thereby providing an i-layer. CONSTITUTION:A molecular sieve or zeolite represented by a molecular formula of Nan(AlO2)(SiO2)27-30 H2O or (K4Zn4) (AlO2)(SiO2).27-30 H2O and having an effective diameter of 2.9-4.65Angstrom is used while being cooled down to a range from the room temperature to -100 deg.C to adsorb impurities of oxide gas (H2O, O2, CO2, etc.) up to a level not larger than 0.03ppm or impurities of gas (CH4, C2H2...) represented by CmHn (m>=2) up to a level not larger than 0.5ppm. Thus, a hydride or halide (with an effective molecular diameter not less than 4.8Angstrom ) of Si or Ge is refined. Reaction gas thus refined can be used to form an intrinsic or substantially intrinsic semiconductor layer by a plasma vapor method. The resultant P-i-N junction can provide a high intrinsic conversion efficiency.

Description

Detailed Description of the Invention The present invention provides a substrate or a first electrode on the substrate, and a non-single crystal semiconductor layer having at least one K PIN junction on the electrode. In a photoelectric conversion device provided by laminating N-type semiconductor layers, an active semiconductor layer that generates a photovoltaic force upon irradiation with light is an intrinsic or substantially intrinsic (Pi or N-type impurity is 4 1 The purpose is to provide an extremely low concentration of oxygen or carbon, which particularly promotes insulation or generates recombination centers, in the semiconductor (artificially or at background levels).

For this purpose, the present invention provides that reactive gases for semiconductors, such as silicide gases such as silane, polysilane, and silicon fluoride, and germanium compound gases such as germane, have an effective molecular diameter of 4.8λ or more. It is something that takes advantage of what we have.

That is, using a molecular sheet or zeolite with an effective pore diameter of 2.9-4.65H, an oxide gas, such as water, which is an impurity having an effective molecular diameter of 4.5 Å or less (hereinafter referred to as molecular diameter) is extracted. (H2O), carbon dioxide gas (co, ts
Oxygen (■, also carbide gases such as methane (C~, ethane (0, IQ), propane (C'J barrel, C to OH, O, H
.

The purpose is to adsorb and remove such substances.

Furthermore, in order to promote this adsorption power, the adsorbent that performs this chemical adsorption is
The objective is to cool the material to 0.00 K and further increase its adsorption capacity by more than 50 times.

Thus, conventional non-single-crystal semiconductors, especially amorphous semiconductors with P-N junctions, have a conversion efficiency of only 6-8% under the condition of A M 1 (100 mW/c♂).
11-14. We were able to increase the intrinsic conversion efficiency to the capital.

In particular, in this active semiconductor layer, the oxygen concentration was increased from 5XIOa to the conventional 2A-4X:L O'-A'.
The density of recombination centers in a semiconductor, for example, a silicon semiconductor, can be reduced to lXl0 Cm by lowering the density to 4x1♂ to 1x10''c♂, preferably 1 x 10 to 1 lXl0 cm or less preferably 5
It is characterized by success in hitting down to ×1♂~lX10”cm'K.

Conventionally, oxygen has locally formed a 5i-0-8i structure in a semiconductor, such as a silicon semiconductor, and has only exhibited insulation properties. However, when several tens of molecules of oxygen gather in silicon to form a cluster, it creates a recombination center for electrons and holes, and acts as a killer of minority carriers generated by light irradiation. It has been found that this effect is also extremely noticeable in non-single crystal semiconductors obtained by plasma vapor phase method to which halogen elements are added. In addition, the dangling bonds of oxygen also act as N-type donor centers, making a non-single-crystal semiconductor semi-amorphous (semi-crystalline, N-type I found out that it turned into

Therefore, when considering industrial applications, it is extremely important to completely remove the oxygen that becomes the donor center and create an intrinsic (Fermi level is lνt゛flq) semiconductor with structural properties. It was important.

Furthermore, regarding carbon, ethane etc. C1nHn (i 2
), it mixes directly into the semiconductor and generates many recombination centers, resulting in a decrease in the lifetime of carriers, especially holes.

The present invention removes such impurities, makes the silicon-semiconductor mainly contain hydrogen or oxygen necessary for neutralizing silicon and recombination centers, and furthermore, the silicon-semiconductor contains hydrogen or oxygen necessary for neutralizing silicon and recombination centers, and furthermore, to increase the Fermi level by 5 feet, impurities 00~3X10'7cm')
It is characterized by the addition of

Conventional silane has an effective molecular diameter of just under 51 (4,8-54,
Also, Germanic has about 61. (Polysilane and the like have an even larger effective molecular diameter.) However, when examining the impurities contained in the reactive gas of, for example, silane (monosilane), which has the smallest effective molecular diameter, Table 1 shows the results.

Table 1 Purity for epitaxial and electronics (%)
99.99 99.9 Hydrogen (ppm)
300 3oo.

Nitrogen 550 Oxygen 0.11 Argon 1050 Helium 10 50 Methane
550 ethane o, 1 0.5 ethylene 0.1 0.5 propane
O, :L 0.5 propylene
O, 10,5 Chloride 1050 Water 35 We investigated these and found that, especially when performing this epitaxial growth, oxides and nitrides are affected by segregation effects during the gas phase-solid phase reaction. It becomes 1/30 smaller. Therefore, a substantially intrinsic semiconductor having a resistivity of 1 ooon or more can be obtained.

However, in the plasma vapor phase method using glow discharge carried out at 100-400'O, the effect of segregation of impurities resulting from such physical purification cannot be expected.

For this reason, the impurities in Table 1 are those! In particular, oxygen mixed into semiconductors reacts with silane,
Create reaction products. As for silane itself, activation (ionization) is only 1 to 5 times due to plasma reaction, and therefore, when a reactive gas is used for plasma vapor phase method, it must be purified in the reactor. Therefore, in the present invention, in order to guarantee the conversion efficiency of xo% or more in AML, the oxygen content in one layer is set to be 5X'LOCm or less,
Furthermore, even in large carbon clusters, 4XIOc
It is extremely important that it be less than m. The present invention aims to improve the purity of such semiconductors.

It is shown below according to the drawings.

FIG. 1 shows an outline of the manufacturing equipment used for manufacturing the semiconductor device of the present invention.

In the drawing, external heating furnace Q91 is used for reaction furnace (1) K.
A substrate (b), a pair of electrodes (3), (3), a high frequency oscillator (2) (for example, 13.56 MHz or 100 KH
z), to further activate and decompose reactive gases,
Microwave with a frequency higher than IGH2, e.g. 2.45GH
The emission of the oscillator α of z, protected by a ceramic α field with an attenuator α, from 0.001 to ml
Microwaves were emitted into the reactor (1) maintained at 1 torr IIC. The entire reactor is shielded (a) to prevent radio wave interference, and the substrate (a) is shielded from reactive gases.
When forming a semiconductor film thereon, an electric field of electric energy is provided parallel to the surface on which the semiconductor film is formed. In addition, the reactive gas was arranged so as to have a laminar flow parallel to the surface on which it was formed. Further, when a silicon film was to be formed, silane, which is a silicide gas, was introduced in step (4). Also, P
Due to hydrogen, which is an impurity for the mold, υ500-, 5000PPM
Diborane diluted with K was introduced into the solution (5), and phosphin, which was similarly diluted with hydrogen, was introduced into the solution (6).

These reactive gases are
These gas purifiers have an effective hole diameter of 2.7 to 4 on the inlet side of the reaction gas.
．． 3 loss of 65λ or 4A, or 4.5A e.g. 4A
Molecular sheep or Zesailite with an effective hole diameter of 3.5P-J4.3^ was used. This molecule 2-thieves or zeolite is Na(AlSin,) 2'7
~30H,O is indicated by 4A, and 4,5A is CKg Z
%) (AIO,) (Sin,)'2'7-30H,
The molecular formula of O shown in τ was used. Furthermore, after this,
Gas Clean (product name Go-RX) for oxygen removal also known as KI
In order to further improve the chemisorption properties of these purifiers,
-70"O - room temperature, e.g. -30" OK
) (9) (10) Cooled to K. For hydrogen-diluted phoschin, 3A or 4A was used because its effective molecular diameter is about 4.3A. Moreover, both 3A and 484.5A were applicable to silane or diborane.

In particular, for silane, in addition to oxygen, which is an impurity that easily converts into N, phosphin forms a surface that is O, 0,
It was particularly effective to use 5A down to IPPA.

Exhaust, tJ! : 21 dollar valve (c), stop pulp (c), and vacuum pump holder were used to exhaust air (c). The pressure inside the reactor is 0.001 to 1 depending on the needle pulp (c).
K was controlled at 0 torr, typically 0.05-0.1 torr.

FIG. 2 shows the characteristics obtained from the results shown in FIG. That is, the substrate temperature z5d'c and the pressure inside the reactor are 0 and 1 Jorr.
When one non-single crystal semiconductor layer is placed on a substrate such as glass,
The light irradiation (A M'l) system when formed to a thickness of μ is 2.

In the drawings, if silane is not purified, impurities in the cylinder as described above will enter the semiconductor layer as is, and oxygen or carbon in particular has the effect of making silicon amorphous. photoconductivity), dark conductivity (
3o) was obtained.

That is, in the drawings, at a high frequency output of 2 o-30 W, the optical conductivity is 10) am), but at the same time, the semiconductor partially becomes Hr quality with 14 properties. Therefore, oxygen, which is an impurity in this semiconductor, becomes a donor center and becomes N-type.

As a result, if it is to be used as an intrinsic semiconductor, boron, which is the opposite impurity, must be added to a concentration of 1≦40 "crn-', or a low high-frequency output of 1 to 5 W/-I
It Ji-fL is not true. However, in all of these, the photoelectric conductivity is 10-txo CfLc
It will be lowered to the order of →.

Instead of such conventional methods, the present invention sufficiently removes impurities in silane after purification (α1 in Figure 1) (141), and also when filling a cylinder with silane.
By doing so, we were able to obtain the light irradiation conductivity (b) and dark conductivity (c) in Figure 2.

As is clear from this drawing, the photoconductivity is as large as 10' (ncm) at a plasma discharge output of 10 W, and the dark conductivity is as low as 10 to 10 (stcn).

That is, the activation energy as an intrinsic semiconductor is sufficiently large, and Fermi Rebelmo/L/1・Ey :';,', e
v I was able to have it.

Further investigation of this property revealed that weak crystallization was observed in the coatings obtained at 5-10W in 19K of X company, and these were semi-amorphous (semi-amorphous) with an intermediate structure between an amorphous structure and a crystallized structure. It could be said to be a crystalline semiconductor.

That is, an intrinsic semiconductor is produced by a plasma vapor phase method of 100 to 3
For example, when attempting to obtain a silane film at 250'C, impurities in the silane tend to enter at a concentration 30 to 100 times higher than in simple OVD or epitaxial growth. Therefore, it is extremely important to use ultra-high purity silane in which the contamination of impurities with decay t@tqV is reduced as much as possible. Thus, even at a low plasma power of 2-10W, the dark conductivity is small and the photoconductivity is 1o(
It was possible to obtain a value of 10 to 10' (JLcn) at the same level as (xcn).

In particular, what can be obtained with such a low high frequency output is that when the P-N junction is gradually laminated with the Pi layer, the N layer, and the N layer as in the present invention, it is possible to clearly strike the boundary area as a surface and create a mixed layer. Furthermore, in Figure 2, adding 2.45 GHz microwave increases the ionization rate of the reactive gas, so although the characteristics were the same, the growth rate of the film increased. I was able to increase the size and make it bigger. For example, 30cc/silane
minutes, O, 1 torr, and high frequency plasma alone was as low as 1-vh7' seconds, but in this case I Ch = 1
5A/II>, high-speed growth was possible.

Figure 3 shows an experiment conducted to confirm the effectiveness of the gas purifier for the purification of silane according to the present invention. (Fourier transform silane-based d oxygen purifier α→, ze÷Lite (11) is the characteristic when the oxygen concentration is used as a parameter for oxygenation, and curve 06) is the oxygen concentration lXl0"cm' [This is a characteristic obtained using the carbon concentration as a parameter. In any case, when 18' am 3 x 101'cm' of carbon and oxygen are mixed, the conductivity is 10 to 11)' (cc, L, It can be seen that the contamination is a factor that causes a decrease in conductivity.

Further regarding the drawing, curve (il) (42) is oxygen,
, ->) Contains a concentration of 3XIOcm and a carbon concentration of 4XIOam, with the carbon concentration and oxygen concentration shown as parameters, respectively. i.e. especially oxygen /& -)
rν zu5XIOc
The photoelectric conductivity can be maintained at 1oCQcd by reducing the carbon content to less than 4XIOcm.
When the temperature was lowered to 50'o, the conductivity decreased by about 1/3.

In order to achieve these oxygen and carbon concentrations, it is extremely important to keep the oxygen in the silane to 0.03 PPM or less.
In particular, if the purification is performed at o'c~30''C instead of the above room temperature, the oxygen impurity concentration will be o, OIPPM.

It can be reduced to 0,003 PPM. Also, O
mHn was able to be lowered to O, IPPM, O, OIPPM K. Then K −'100'o K
? ) It is completely impossible to measure with an analyzer. Furthermore, in order to obtain the high purity of the semiconductor formed as described above, the total leakage amount must be increased to 1× even in the reaction system shown in FIG.
10-'acc//sec or less, better ha1x16'
4 is formed using the manufacturing apparatus shown in FIG. 1, so drawing (A) shows the transparent conductive film (33) on the glass substrate
, and further KP-type silicon S i x O14 (0< x
(1) (e.g. x=0.8) or P-type silicon semiconductor (3
After cleaning, an intrinsic semiconductor layer was formed with purified silane to a thickness of 0.5 μm K(31). Further, vacuum was applied again, and an N-type semiconductor layer (31) was formed by mixing silane with phosphin at a concentration of 1% to a thickness of 200 mm.

After this, the aluminum (36) in (b) was vacuum-deposited.

The escape power on the high side was 5 W, and the substrate temperature was 200'C. As a result, a conversion efficiency of 10.3% could be obtained.

In order to further improve the characteristics of this glass substrate, Fig. 4 (B
) A P-type N junction photoelectric conversion device was fabricated.

In the drawing, a stainless steel substrate (3-layer KP-type semiconductor layer (34), N-type semiconductor layer (33), transparent conductive film 03) is coated with TO (indium oxide (tin oxide)). 10%)) was vacuum evaporated and an auxiliary electrode (36) of aluminum was provided.

FIG. 5 shows the conversion efficiency characteristics of the photoelectric conversion device using the oxygen concentration mixed in the intrinsic semiconductor layer as a parameter in the structure shown in FIG. 4(B).

Oxygen concentration is 4X10"am"1. IM lower special K lXl0
When it becomes less than ``am'', the conversion efficiency of 1 was able to exceed 12% in an area of 1 cm with AMI K.The curve ψ of 1 also exceeded 0.7, and the short circuit current in particular exceeded 20 mA/cmL at the maximum. The open-circuit voltage was 0.86-jo, 93-te.Then, the oxygen concentration was small, and by making silicon more like silicon, a significant improvement in properties was observed. Ta.

In the embodiment shown in FIG. 4(B), the N-type semiconductor layer is a polycrystalline semiconductor having a fiber structure, and the layer is 200-250'
Regarding the production of O at low temperatures, it is shown in the patent application filed by the present inventor (Or No. 7.j, 29th Edition).

In the above explanation, a photoelectric conversion device having one P-N junction was shown, but if this is stacked, the PINP-N junction...
- It is also important for applications of the present invention to have at least two junctions, including a P-N junction, and these may be integrated on a substrate.

Furthermore, in the explanations so far, silica/especially monosilane has been shown as the silicide gas. However, the present invention can also be applied to polysilanes such as 3 and '-5 because of their large effective particle size, and
14 is similarly effective because its molecular diameter is as large as 5'A. Regarding germanium, 5ixGe,
It is also possible to use only Ge (o < x < 1) or Ge alone in the semiconductor layer included in the P-N junction.

In the above description, a photoelectric conversion device having one P-N junction was mainly explained. However, the conductor layer has at least one N-type or P-type junction, i.e., N(source l1
t1rLs (channel formation region) N (Is
``b (or source), an insulated gate field effect semiconductor device having a P-type junction, or a p-type field-effect semiconductor device having a p-type
The present invention is also extremely effective for transistors having junctions.

[Brief explanation of the drawing]

FIG. 1 shows plasma characteristics for manufacturing a semiconductor device according to the present invention. FIG. 3 shows changes in electrical properties obtained by the gas purification method of the present invention. FIG. 4 shows a photoelectric conversion device of the present invention. FIG. 5 shows the profitability of the photoelectric conversion device obtained from FIG. 4(B). 106 10 1σ' 10” 1σ710” 1
σ9 Gourmet Guanlin Leading Formation (.l) Figure 3

Claims (1)

[Claims] 1. At least one P-type and N-type junction provided on the substrate
In the method for manufacturing a semiconductor device, the intrinsic or substantially intrinsic fast conductor layer constituting the engineered semiconductor layer is
At least the impurity concentration of oxide gas is kept at a concentration of 0.03 PPM or less, or the impurity concentration of carbide gas represented by OmHn (m22) is kept at a concentration of 0.5 PPM or less. 1. A method for manufacturing a semiconductor device, characterized in that the semiconductor device is formed by a plasma vapor phase method. 2. In claim 1, the reactive gas such as a hydride or halide of silicon or germanium is produced by a molecular sheep or zetlite having an effective hole diameter of 75: 2.9-4.65A. A method for manufacturing a semiconductor device characterized in that the molecular sheep or zeolite is NEL, (410,) (Sin,) 2'7 to 30
H, O or (K, Zn,) (A10.) (Sin,
) A method for manufacturing a semiconductor device, characterized in that the semiconductor device has a molecular formula represented by 2'7 to 30HLOK. 4. In claim 2, molecular tube or i ψ2 b) I, i: chamber, -□. . A method for manufacturing a semiconductor device characterized by OK cooling. The present invention relates to a photoelectric conversion device having at least one P-N junction and a method for manufacturing the same, using a high-purity semiconductor manufacturing gas.