JPS5825282A - Photoelectric transducer - Google Patents

Abstract

PURPOSE:To effect highly efficient photoelectric conversion by laminating semi- amorphous n type and p type layers and an intrinsic or substantially intrinsic layer of amorphous substance which is produced in such a manner as H2, halogen or alkaline metal is added to the n type semi-amorphous silicon on the side of the light incidence surface. CONSTITUTION:A p type layer 53, intrinsic layer 51 and n type layer 52 of silicon are formed on a metallic substrate by CVD plasma process adding SiH, B2H6, PH3, and NH3. The layer 56 is amorphous AS, and the layer 60 gradually grows SAS of semi- amorphous substance in the direction of an electrode 54. Electromagnetic energy is increased as the intrinsic layer is accumulated and Fermi level is caused to come closer to the conduction band to promote mobility of the holes and to increase current flow. In addition, optical absorption is reduced by changing the n type layer 52 and its neighborhood into SAS to cause holes to be generated at deeper level. Therefore, diffusion distance of holes to the electrode on the reversed side can be shortened so as to increase electric current. When the p type layer 53 is formed on the substrate, the layer is caused to compose two layers, SAS and AS layers, and conduction bands and valence bands are continuously junctioned at the hetero junction faces. By such a setup, highly efficient photoelectric conversion can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device using a non-single-crystal semiconductor, particularly to a semiconductor device using an intrinsic or artificial P or N-containing impurity that has a photovoltaic effect that generates a pair of spots and holes when irradiated with light. Regarding a so-called substantially intrinsic semiconductor layer (hereinafter simply referred to as one layer or simply an intrinsic semiconductor layer) and a P-type or N-type semiconductor layer, the present invention provides hydrogen, fluorine, or Contains chlorine elements such as chlorine or alkali metal elements such as lithium, sodium, and potassium, and typically contains 6 to 2000 μm, typically 6 to 10
Semi-amorphous (semi-amorphous) semiconductor (hereinafter referred to as 8A8) having crystallinity of 0 μm size (crystallinity of short range order) and amorphous (non-crystalline) having no crystallinity of such short range order. A semiconductor (hereinafter referred to as A8) is provided in a layered structure.

In particular, in the present invention, the N-type semiconductor layer on the light irradiation surface side of the photoelectric conversion device is made of 8A8 in order to reduce the absorption of incident light in that region, and the intrinsic semiconductor layer adjacent thereto is made of 8A8.
A8, the carrier time on the incident light side is lengthened, and a semiconductor layer mixed with S or As is stacked on the top surface of this 5AEI in an intrinsic step-like or continuous manner to increase the internal electric field. It was established voluntarily to encourage improvements in light-to-electricity conversion efficiency.

Regarding 8A8, a patent application filed in 1986-0 is filed in accordance with the present invention.
26388.855.3.3 application (semi-amorphous semiconductor) is known 0 In addition, a patent application filed in the form of the present invention is filed as an invention in which a P-N junction type photoelectric conversion device is provided using this 8Alil. Showa 66-oosa99.856
．． 1.22 (photoelectric conversion device) is known. Further, an application of the present invention is filed as a semiconductor device using these 8 MU S and MU 8 or providing a window structure for an N-type semiconductor layer (US Patent No. 239.5541880.12)
．． 6 Issued US Patent 4.254.4291981.3.
3 issue) is known. The present invention is a further development of the application that constitutes the invention of the present invention type.

Furthermore, in the present invention, S and Si2 differ in various physical properties), and there are extremely large differences in light absorption coefficient, photoconductivity, activation energy and ionization rate when p- or N-type impurities are added. . The present invention will be described below with reference to the drawings, in which a highly efficient photoelectric conversion device is provided by organically combining respective semiconductors.

FIG. 1 shows an outline of a plasma OVD apparatus necessary for implementing the present invention.

In other words, the substrate (1) is a quartz holder (Bo) (2) K
Parallel to the flow of gas in the reactor (e), the body was injected with silicide gas (8iXHam H21) (6), and diborane (4), which is an impurity for P-type, and N. .

In addition, additives with a wide energy range, such as TM (tetramethylsilane (1), 81), are supplied by pulling them through a bubbler with He and E. Also, ammonia (NH), carbonized Hydrogen such as OH.

C, H4 may be used.

These are passed through a mixer a″i) and microwaved (1 to 10G
By applying secondary electromagnetic energy to the exciter ()) to the reactive gas or carrier gas by 1 t (LO to a energy) of Hz (typically 2.45 GHg), these gases are activated and decomposed. It was introduced into the reaction vessel member through the inlet (9). In this reaction vessel, a substrate (1) having a DC to 20 MHs surface was heated in a K resistance heating furnace (5) to a temperature of 500°C, typically 300°C, so that a large amount of substrates could be processed. The product was formed on a heated substrate using secondary energy such that the film was spread and hardened on the surface to be formed. Furthermore, the carrier gas and impurities are discharged to the outside through the exhaust port (6), the valve a1), and the rotary pump 4. The pressure inside the reaction vessel is 0.1 to 1 Otorr, typically 0.3 to 1tOrr, fr-0. The second figure shows a substantially intrinsic semiconductor film to which no impurities are added. The figure (&) indicates the optical absorption coefficient of the secondary 'a magnetic energy, φ) indicates the carrier diffusion length or photoconductivity, and (0) indicates the activation energy.0 As shown in Figure 2 (1). As shown, the area of As (36) and 8
Area of A8 < The light absorption coefficient is different from SPQ. 8 AS tends to be smaller. 0 Drawing (4) has a wavelength of 500 nm.
In addition to the secondary magnetic permeability energy, the reactive gas decomposes the secondary electromagnetic energy and activates it to the extent that the reaction does not occur. From curve (32), (31
9 This means that the growth rate of the formed film is 3 to 5.
Since the density is also the same as above, it is presumed that the increase is due to high density.

Curve (34) in Figure 2 (g)) is 13.56MH
g of secondary electromagnetic energy alone, or the curve (the third row shows the case where microwaves are added. In either case, when the photoconductivity becomes 81S (3)), IX l 6' ~ 8 X 16
(High values of Aom5' were obtained, which were very close to those for single-crystal silicon.

Furthermore, the activation energy decreases, and the diffusion length of electrons becomes extremely large, indicating a tendency to become N-type.

In the intrinsic semiconductor (including substantially intrinsic conductor) region of the present invention, As and Si2 are formed in the stacking direction of the formation surface.
The present invention aims to obtain a photoelectric conversion device with high conversion efficiency by discontinuously or continuously changing the J4ss'Jt properties in a layered manner.

Figure 3 shows MuB or 8A having P or N type conductivity.
8, especially 0.2 to 2 units such as B, H4/
This is the data when BIH2・0.5% and PHk/SiH4・1ch.

FIG. 3 (A) shows the relationship between secondary electromagnetic energy and optical absorption coefficient, (B) shows impurities and activation energy, and (0) shows the energy band width.

In Fig. 3 (4), the curve (41) is 500% of silicon only.
The absorption coefficient in nm is shown. Here too, A8 (3
Compared to 6), the absorption coefficient is about 1 for Smuday (3)).
You can expect a window effect from /3 to January 30. In addition, carbon should be added to this silicon to form an EIiO bond (07
It is doped with 0.2 to 0.4 Si, and the energy band width is 1.6 eV p2. .

Since the evic can be widened, the absorption coefficient at 500 nm K is reduced and curve (46) can be obtained. Especially when converting to 8A8, the secondary electromagnetic energy is 60~S
If OW is assumed and the secondary electromagnetic energy is 30 to 100W, then 1
A low value of ~3XIOo was obtained.

8A8 can also be clarified from the activation energy shown in FIG. 3 φ). Curve (2) is for secondary electromagnetic energy only, and curve 03) is for magnetic energy of 30 to 1.
The case where 00W is added is shown.

As is clear from the drawing, when microwaves are used to apply electromagnetic energy to a light element such as hydrogen at a position far from the formation surface, a lower secondary energy is generated without imparting kinetic energy to heavy molecules or associated molecules. It can be seen that the 8A8 structure having microcrystallinity can be approached by changing the energy.

The present invention reduces the secondary energy to 100W or less, especially 60W (S
P or N in a PXN type photoelectric conversion device that includes these two intermediate structures as A B) and 20W (As).
If a semiconductor layer with a different structure is stacked on the type semiconductor layer, the high i
This is an attempt to obtain e-+.

4 and 5 show a vertical sectional view and an energy band diagram of the photoelectric conversion device of the present invention.

In FIG. 4, a P-type semiconductor layer (53), an N-type semiconductor layer (sl), and an N-type semiconductor layer (counter electrode C54 on a transparent conductive film 52L) are provided on a metal substrate, such as a stainless steel substrate, and irradiation light ( 55) An attempt was made to obtain a photovoltaic force by transferring electron-hole pairs (5υ to the P-type layer Q and N-type layer O52) to the internal electric field) generated in the Yoshie-type layer (5]). It is something.

An example energy band diagram corresponding to Fig. 4 (4) is shown in the same figure (
B) shows corresponding numbers. Drawing smell (56)
) is As, and (60) is 8A8' electrode (54
) 0 This EI is gradually increased in the direction
As the AS ratio increases, that is, as one layer is stacked, as the electromagnetic energy increases as shown in Figure 2 (0), the Fermi level approaches the conduction band, and as a result, the lower left becomes 9. An internal electric field can be obtained. As a result, holes can easily drift toward the substrate in the valence band, and the apparent diffusion length can be increased, resulting in an increase in current. In addition, by making the N layer (52) and its surrounding area 8x8, light absorption in this area is small, and holes with short diffusion lengths are generated in the N layer (52). It can be internal rather than in the immediate vicinity. As a result, the effective diffusion distance of holes to the back electrode can be shortened, and a large current can be generated even on this surface.

Furthermore, when forming a P layer on the substrate, this P layer also has an 8A
The 8-layered region (6 layers, MuB region (64) is stacked in two layers to improve the structural sensitivity at the P-C junction interface. It was important that the bands be joined continuously.

Such As, SA8 when changing the 8 layer days continuously
Figure 6 φ)K shows an example of the conversion rate. In the drawing, the N layer (52) and the P layer (53) are 858 in size, and the semiconductor layer (52), which can bring about a window effect, has a wide energy band width and serves to reduce the absorption coefficient.

With this structure, it was possible to obtain a permeation current of 20 to 30 mm and 10 rbL, and the conversion efficiency was also able to be increased to 1 to 6 chi.

FIG. 6 shows a transparent conductive film (6 layers) on a transparent substrate (58).

P-type semiconductor layer (53L engineering type conductor layer (al) I) N-type semiconductor layer (5, consisting of a back electrode (59) that becomes a transparent conductive film ◎ In drawing (4), the engineering type semiconductor layer is Layer (60) @ (
6]) *(a”) * (56) is formed and its 8A
The Li conversion rate is set to 0, 25, 50, and 75%, respectively.

In this result, the energy band was found to be step-like.

In other words, in this structure, from the light irradiation surface to the inside, the electrons and holes change to 9SA8 and promote the drift of electrons and holes generated at a position away from the Lp layer to the surface. I was able to increase it.

In FIG. 6(B), one layer was simply prepared by dividing it into 81 days and 8 days. In this case as well, Fig. 6 (4) shows that the internal electric field is very small.
It was possible to increase it from mA10n to 1 full 20mA10 m'.

In the present invention, since 8A8 has a structural sensitivity similar to that of a single crystal semiconductor compared to As, after these P-N junction structures are fabricated, TtL magnetic energy is applied to ionize hydrogen and plasma Hydrogen annealing was also effective in ensuring the reproducibility of variations in this photoelectric conversion device.

In the case of secondary electromagnetic energy, this ionization has a sputtering effect because it is ionized onto the substrate, and on the contrary, the characteristics have been deteriorated.

Therefore, the ionization rate is 13.56MHH compared to lO
'It has an extremely large effect on ionizing the ions at a distance from the substrate using microwaves of 2.45 GHg, which is 10 times larger, and impregnating the substrate by diffusion to neutralize the dangling bonds. Similarly, an alkali metal such as lithium is dissolved in water with lithium hydroxide, and the semiconductor device is immersed in it, heated and diffused at a temperature of 300" or less to a low concentration of 1♂ to 10" to form a recombination center. Neutralizing it is highly effective.

As is clear from the above description, in the present invention, the semiconductor layer is formed by laminating or continuously controlling the ratio of S and S in the semiconductor layer of the same conductivity type. As a result, instead of controlling the impurity concentration in the semiconductor layer to change the position of the Fermi level and thus creating an internal drift electric field, as is known in the art for single-crystal semiconductors, The invention has a major feature of changing the position of the shift ermi level by controlling the crystal structure of the semiconductor between 8 and 8 and creating an internal drift electric field without adding impurities. I have 1.

As a result, the drift of electrons and holes in the intrinsic semiconductor is promoted, and in photoelectric conversion devices, especially PI using MuS
Compared to the N-type structure, the current could be increased by 30 to 300 inches.

The present invention is applicable to PIN type diodes and is particularly effective in photoelectric conversion devices using the same. However, in other semiconductor devices such as P-type N diodes, image sensors, diode arrays, light-emitting diode phototransistors, insulated gate field-effect semiconductor devices, and integrated circuits, P-type semiconductor layers, N-type semiconductor layers, type 1 (intrinsic or The technical idea is to locally provide MU S and 8 MU S in a semiconductor layer of the same conductivity type (substantially intrinsic).

The present invention is based on the experimental fact that M8 and 8A8 can be controlled by the same plasma OVD apparatus, and we believe that the industrial effects thereof will be extremely large.

Note that the present invention has been mainly described with reference to silicon or a compound (mixture) of silicon and carbon or nitrogen.

However, germanium and iv compounds can be similarly applied.

[Brief explanation of the drawing]

FIG. 1 shows a manufacturing apparatus for manufacturing a semiconductor device of the present invention. Figure 2 shows the electrical and physical properties of an intrinsic semiconductor. Figure 3 shows the physical and electrical properties of a Pt or N-type semiconductor. 4 and 5 are vertical cross-sectional views of the semiconductor device of the present invention and energy band diagrams corresponding thereto. FIG. 6 shows three embodiments showing mixed stacking in place of amorphous and semi-amorphous semiconductors. Bon, Fujiku: l-ノV壓-too(w) V pxshii-7しノ~;-jshi・nondobshiI)23
Figure ￥5 figure

Claims (1)

[Claims] 1. A first N or P type semiconductor layer having a semi-amorphous semiconductor having a microcrystalline structure is provided on the light irradiation surface side, and hydrogen for neutralizing recombination centers is provided on the semiconductor layer; An intrinsic or substantially intrinsic amorphous semiconductor to which a halogen element or an alkali metal element is added, and a semi-amorphous semiconductor having the same conductivity type as the semiconductor layer are provided on the semiconductor, and the first semiconductor layer is provided on the semiconductor. A photoelectric conversion device characterized in that a second semiconductor layer of a conductivity type opposite to that of the second semiconductor layer is provided. 2. A photoelectric conversion device according to claim 1, wherein the first and second semiconductor layers are made of a semiconductor containing a mixture of silicon and carbon or nitrogen. 3. A photoelectric conversion device 0 according to claim 1, characterized in that the intrinsic or substantially intrinsic semiconductor has silicon as its main component.