JPH02377A - Photoelectric converting device - Google Patents

Abstract

PURPOSE:To improve efficiency of a photoelectric converting device, by constructing the device such that an electric field is generated between P- and N-type region in the direction parallel with the irradiated surface and a second has a width of energy band larger than that of a first semiconductor. CONSTITUTION:A first semiconductor 2 is formed on the top face of a substrate 1 and a second semiconductor 3 is further formed thereon. Then, opening 7, 8 are formed by sectively removing the parts of an insulating film 4 where positive and negative electrodes are to be formed. The second semiconductor 3 is doped with boron B and phosphine through the openings 7 and 8, respectively, so that a P-type region 9 and an N-type region 10 are formed in the second semiconductor layer, respectively. The dopants are diffused into the first semiconductor so that a P-type region 19 and an N-type region 20 are formed, respectively. Then aluminum is vapor deposited on the top faces of the P-type and N-type regions 9, 10 for producing ohmic contact electrodes 14, 15 as well as external contact terminals 16, 17 extended therefrom on the substrate.

Description

[Detailed Description of the Invention] r Industrial Field of Application 1 The present invention selects a P-type region that will serve as an electrode and an N-type region that will serve as one electrode only on one main surface of a semiconductor provided on a substrate. The present invention relates to a photoelectric conversion device that is easily provided, easily manufactured, and has a simple structure.

``Conventional technology j'' Conventionally, solar cells or photocells in which a PN or PIN junction is formed on a single-crystal silicon substrate are known as photoelectric conversion devices.However, this PN or PIN junction is formed on a single-crystal silicon substrate. It has ten electrodes or one electrode on the front and back surfaces, and the bonding surface is arranged substantially parallel to the main surface of the substrate, so that a large amount of light is irradiated onto the bonding surface. It wasn't too much.

Problem to be solved by the V invention 1 Since these conventional photoelectric conversion devices have a bonding surface parallel to the main surface of the semiconductor substrate, the direction in which the electric field is applied and the light irradiation surface are perpendicular to each other, resulting in a decrease in the light irradiation intensity. The electric field was not uniform in the direction in which it was applied, making it impossible to efficiently generate electrons and holes.

In addition, single crystal substrates have many drawbacks, such as being extremely easily cracked and expensive, difficult to process, and unable to integrate photoelectric conversion devices and arrange a plurality of them in series or parallel.

The present invention is directed to a photoelectric conversion device that can efficiently generate electrons and holes in a non-single crystal semiconductor, and further uses a non-single crystal semiconductor.

"Means for Solving Problems" The present invention has a first semiconductor on a substrate and a second semiconductor on the semiconductor, the first semiconductor, the second semiconductor, or the first semiconductor. and P in the second semiconductor.
The above object has been achieved by a photoelectric conversion device characterized in that it has a type region and an N-type region, and electrodes are provided on the P-type region and the N-type region.

1 Effect j The structure of the photoelectric conversion device as described above, that is, by forming the P-type region and the N-type region in the depth direction of the semiconductor from the same light irradiation surface, the P-type region and the N-type region are formed in the depth direction of the semiconductor. The light intensity in the electric field direction between regions is constant. In particular, when the second semiconductor is made to have a wider energy band width than the first semiconductor, the vicinity of the electrode has a substantially W-N structure (WIDE-
T.

NARROW) and the electrons generated by photoexcitation.
It is designed to improve photoelectric conversion efficiency by diffusing and collecting electrons in ten electrodes and holes in ten electrodes and electrons in one electrode, without causing electrons to diffuse to one electrode among the hole pairs. This is what I tried to do. The present invention will be described below with reference to Examples.

rExample IJ FIG. 1 is a longitudinal sectional view showing the manufacturing process of the present invention.

In FIG. 1(A), the substrate (1) is a conductive or insulating substrate. The requirements for this substrate are that it is inexpensive and has mechanical strength and heat resistance for the subsequent film forming process. Therefore, in this embodiment, chinaware, ceramic, or glass substrates were mainly used. Deposition was performed on the upper surface of this substrate (1) for about 60 minutes at a temperature of room temperature to 500°C using SiH4: 20SCCM and a pressure crab of 0.01 to 0.3↑ORR to give a film thickness of 1 μm and an energy band. A first semiconductor (2) having a width of about 1.6 eV was formed.

At this time, the energy band width may be changed by adding a gas containing C, O, and N to the source gas as necessary. Furthermore, a second semiconductor (3) was formed on this first semiconductor (2). However, in order to make the energy band width about 0.5 to 2 eV wider than that of the first semiconductor, 5 to 50 μm of N, -0, and C were added to the reaction gas under the same manufacturing conditions as the first semiconductor.
A second semiconductor with an energy band width of 2.3 ev and a film thickness of 2,500 tm % was formed.

These first semiconductor and second semiconductor were substantially intrinsic semiconductors unless P-type and N-type dopants were added.

Next, after etching this semiconductor so as to leave only the portion necessary for the photoelectric conversion device, an insulating film such as silicon oxide or nitride, which has a masking effect on the second semiconductor, is formed on the upper surface and around the sides of the semiconductor layer. Silicon was formed to a thickness of 500 to 2000 layers by plasma CVD. In this example, 5il14. Silicon nitride was formed using N113.

Further openings (7) for the parts that become ten electrodes and one electrode.
, (8) is formed into an insulating film (4) by photo-etching.
was formed by selectively removing. The width of this opening is 2 to 20
It is a comb shape with a narrow width, especially 5 to 7 μm, and the opening (7
The distance (11) between ) and (8) was made almost the same as the film thickness of the first semiconductor, but this distance is shorter than the diffusion distance of electrons and holes generated by re-excitation in the semiconductor and is 1/1/2 the distance.
It was best to set it to 4 to 1/2. Further, the opening may have a shape such as a tanzak shape. Next, the opening (7), (
8), boron (B) and phosphine (P) were added as dopants by diffusion method, ion implantation method, etc.
cm-” to a concentration of 3 mo1%, Figure 1 (C
), a P-type region (9) and an N-type region (10) were formed in the second semiconductor layer. Furthermore, since the first and second semiconductors are both non-single crystal semiconductors, impurities diffuse into the first semiconductor, forming P-type regions (19) and 19, respectively.
It becomes an N-type region (20), and its depth is kept within 0 to 2000 depths from the interface between the first semiconductor and the second semiconductor.

This is because if the depth is deeper than this, the distance becomes longer than the carrier diffusion distance, and the carriers disappear midway.

Next, as shown in FIG. 1(D), 1 μm of aluminum is deposited on the upper surface of each of the P-type region (9) and the N-type region (10) to form an ohmic contact electrode (14).

External connection terminals (16) and (17) were formed on the substrate (15) and extending therefrom.

The light enters as shown in (25) above and becomes essentially an intrinsic second light.
Since the semiconductor (12) has a window effect with respect to light, its thickness was selected to be 4/4 of the incidence of incident light to promote its effect as a so-called anti-reflection film.

If you consider the energy and hand diagram according to the broken line A-A' in Figure 1 CD), the second example is
Figure (A) was obtained. Ten electrodes (14) second P-type region (9
), a first P-type region (19) a substantially intrinsic first semiconductor (2) a first N-type region (20) a second N-type region (
10) , -corresponding to the electrode (15), respectively (14)
, (9) , (19), (2), (20), (10)
, (15) are written.

As is clear from this Figure 2 (A), the hole is (14)
The electrons also diffuse to (15), and if some of the holes diffuse to (10), they will be repelled by the wide energy band of the second semiconductor, causing Recombination is prohibited. Similarly, recombination of electrons with holes in the vicinity of the ten electrodes is prohibited by the second semiconductor (9).

From this, the present invention not only has a W-N structure with respect to the incidence of light, but also has a wide energy band width that favorably contributes to each of electrons and holes. We were able to create a W-N-W sandwich inch structure.

As a result, it was found that the photoelectric conversion efficiency was improved by 0 to 200% compared to when the semiconductor in the cylinder 2 had the same energy band width as the first semiconductor, and in this example, it was 4.20% at 0.01eI11. Efficiency is obtained, and if the area is small, 12 to 16
% efficiency was found.

Figure 2 (B) shows a P-type region (19) and an N-type region (20
) is formed in the first semiconductor layer, and inhibits recombination of electrons or holes more actively than in (A).

FIG. 2(C) is an energy band diagram shown along the broken line B-B'' in FIG. 1(D).

rEmbodiment 2J As shown in FIG. 3(A), this embodiment has a structure almost similar to that of Embodiment 1.

However, between the first semiconductor and the second semiconductor, there is an insulating layer (50
) is provided. This insulating layer (50) has a thickness of 2 to 50 layers, particularly 2 to 30 layers, which allows tunneling current. The flow rate ratio of 5il14 and NH3 as raw material gas is 1
: 30. Silicon nitride was deposited for about 20 minutes at ITorr, 30-. The rest is exactly the same as in Example 1.

As a result, the ten electrodes and the negative electrode have an MIS structure (P semiconductor-insulating film-first semiconductor or N semiconductor-insulating film-first semiconductor).

Since an insulating film is inserted between the first semiconductor and the second semiconductor, when forming the P-type region and the N-type region, impurities are removed from the first semiconductor.
It was possible to fabricate the bottom surfaces of the P and N regions substantially adjacent to each other between the first semiconductor and the second semiconductor without penetrating the semiconductor layer. This made it possible to shorten the carrier diffusion distance.

FIGS. 3(B) to 3(D) show cross-sectional views of other embodiments of the present invention.

In the present invention, the semiconductor material may be not only a silicon-containing semiconductor but also a m-v group or n-IV group compound semiconductor, and as long as its structure is non-single crystal, it may be so-called amorphous, semi-amorphous, or polycrystalline. Also, the method for producing it may be a known chemical vapor phase reaction method.

V. Effects of the Invention The photoelectric conversion device of the present invention typically has a structure as shown in Figure 1 (D).

The direction of the electric field generated between the P-type region and the N-type region is parallel to the light irradiation surface, and the energy band width of the second semiconductor is 0.0% compared to that of the first semiconductor. By forming a wide range of 5 to 2 eV, the vicinity of the electrode is substantially WI DE-T.
It has an o-NARROW structure, and electrons to the ten electrodes, -
The movement of holes to the electrodes was reduced, making it possible to create a highly efficient photoelectric conversion device.

Furthermore, since the second semiconductor has a window effect and chemical stability, incident light is efficiently guided to the semiconductor layer, and the second semiconductor has a window effect and chemical stability.
We were able to suppress leakage between the two electrodes.

Also, by making the semiconductor non-single crystal, it has become easier to process the semiconductor.

Other features include that the external lead-out electrodes are formed on the substrate, which allows multiple photoelectric conversion devices to be integrated on one substrate and connected in series or parallel, and backflow prevention diodes can also be installed on the same substrate using the same semiconductor. It can be made.

Since the electrode is formed only on one surface, there is no need to consider thermal stress during semiconductor manufacturing.

The structure is extremely simple, and since the top and periphery of the semiconductor are covered with a silicon nitride film, it has excellent reliability against external contamination.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the manufacturing process of a photoelectric conversion device having a structure according to the present invention. FIG. 2 is an energy band diagram of FIG. 1(D). FIGS. 3A, 3B, 3C, and 3D are vertical sectional views of other embodiments of the present invention. ■...Substrate 2...First non-single crystal semiconductor 3...
...Second non-single crystal semiconductor 4...
Engraving of insulating film drawings (no changes in content) Figure 1 Figure 1 Procedural official document (method) 1. Display photoelectric conversion device 3 of the case, person making the amendment Relationship with the case

Claims (1)

[Claims] 1. A first semiconductor on a substrate and a second semiconductor on the semiconductor, the first semiconductor or the second semiconductor or the first semiconductor and the second semiconductor. The semiconductor has a P-type region and an N-type region, and the semiconductor has a P-type region and an N-type region, and
A photoelectric conversion device characterized in that an electrode is provided on a region of a mold. 2. A photoelectric conversion device according to claim 1, wherein the energy band width of the second semiconductor is larger than the energy band width of the first semiconductor. 3. A photoelectric conversion device according to claim 1, characterized in that an insulating or semi-insulating region is provided between the P-type region and the N-type region.