JPS5823490A - Optoelectric transducer - Google Patents

Abstract

PURPOSE:To utilize incident light at its maximum with high efficiency by forming the antireflection film of a section with no electrode in predetermined thickness in the optoelectric transducer for a photosensor or a solar cell. CONSTITUTION:A semiconductor substrate 1 is thermally oxidized in an oxygen atmosphere, and a silicon oxide film is formed. Resists are selectively shaped to the peripheral section of the surface and the back of a semiconductor 1, only the upper surface of the semiconductor is exposed through selective etching, and the ARF3 of an oxide is formed to the whole upper surface is such a manner that it is added to a substance such as TiOx and P2O5 is mixed to TiOx by 0.1-10%. The antireflection film made of TiOx, etc. is shaped through heating. resist films 5 are printing-formed except electrode window holes 8, 8' by using a screen mask through a printing method, etc., the ARF in the window holes 8, 8' is removed by an acidic etching liquid, and the surfaces of a semiconductor layer 4 are exposed at 10, 11. The whole is immersed in a nickel electroless plating liquid forming a metallic electrode, and nickel is deposited and plated onto the surfaces 10, 11 of the semiconductor and the resist films 5. The resists are removed by an organic solvent, and unnecessary metal is lifted off. Accordingly, the external extracting electrode hole 8 and the pectinate type electrode hole 8 also take the same form, and an electrode 13 and an external extracting electrode 12 shaped while the metallic electrodes are fast stuck onto the semiconductor layer are formed.

Description

[Detailed description of the invention] The present invention relates to a photoelectric conversion device and a method for manufacturing the same.

The present invention is intended to be used as a photoelectric conversion device, particularly a 7-otosensor or a solar cell, and after forming this anti-reflection film, this film is selectively removed with a resist, and this same photoresist is used to remove this film. - A metal electrode is formed only on the removed window hole portion having the same shape by electroless plating, and the other portion is removed by lift-off method.

By using such a self-line method using the same window hole, conventionally, an anti-reflection film was covered above the electrode portion, making it difficult to electrically connect it to the external lead-out electrode. These conventional drawbacks can be eliminated, and since the side of the electrode uses the same window hole, it is adjacent to the anti-reflection coating.
I can do it. Therefore, all of the antireflection films in the areas without electrodes can be formed to have a constant or substantially constant thickness and have the same planar shape with respect to the upper surface of the substrate. Therefore, it has the feature that it is possible to use the most celestial eye of the incident light with high efficiency.

The present invention also includes forming an antireflection film on the upper surface of a semiconductor of one conductivity type using titanium oxide, silicon oxide, tantalum nitride titanium oxide, etc. by a coating method or screen printing method, and then diffusing impurities into the semiconductor. The present invention relates to a method of forming a semiconductor layer. That is, in this anti-reflection film (hereinafter referred to as ARP), impurities constituting a conductivity type opposite to that of the semiconductor, such as P.
In the case of a type semiconductor, a phosphorus compound such as phosphorus pentoxide is added to the ARP, and after the formation of the ARP, the
Heating for 10 to 30 minutes at a temperature of
The present invention relates to a method of forming an impurity layer of opposite conductivity type by diffusing valent or V-valent impurities.

The present invention further provides that during electroless plating of nickel, impurities similar to those in the semiconductor layer, such as 91-valent (for example, boron), V
The present invention relates to providing a photoelectric conversion device having high reliability by doping impurities such as phosphorus and forming a metal film, such as a nickel film, containing these impurities.

FIG. 1 shows a vertical sectional view of an example of a conventional photoelectric conversion device including its manufacturing process.

In the drawings, a semiconductor substrate (1), for example, P type 1 to 3A-c
An N-type semiconductor layer (4) is formed on the surface of m. Furthermore, an aluminum film with a thickness of 0.5 to 1 .mu.m was formed on this upper surface. Furthermore, unnecessary material (10) is selectively removed by a photo-etching process using the resist α2 as a mask.

Thereafter, as shown in FIG. 1(C), an anti-reflection layer (6) is applied to cover the insulating film (5) on the semiconductor surface and the counter electrode (10) to reduce the refractive index to 1.8-2. A second film is formed.

In the conventional method made using this method, a strong acidic solution is used to etch the metal electrode in the region (a) where the light passes through, which is likely to cause damage.

Furthermore, an anti-reflection film (3) is applied to this counter electrode (7).
Although it has the characteristic of preventing mechanical damage to the electrode, it is necessary to selectively form an electrode hole for external extraction in this antireflection film in order to maintain electrical continuity between this electrode and the output. Moreover, if this antireflection film (6) is attempted to be formed by depositing SiO or the like using a vacuum evaporation method, the side portions of this electrode will be difficult to evaporate and become extremely thin. As mentioned above, when the coating method is applied, the original 700 to 10 is applied only to this side member.
The thickness is not 0OA, but 5000A to 1μ, and thermal distortion between the applied antireflection film and the electrode 00) deteriorates reliability, making it extremely difficult to put it into practical use from an engineering perspective. In order to eliminate such drawbacks, the present invention first forms ARP in a planar shape on the upper surface of the semiconductor (1), then selectively removes this ARP, and connects only the removed portion with a counter electrode in the same window hole. As a result, a specific process unlike the conventional method is not required for attaching the external lead electrode for continuity between the output and the counter electrode on the counter electrode. Since the anti-reflection film is not formed around the side of the counter electrode, it is not formed thickly, and the anti-reflection film is formed on the substrate with a relatively thin thickness and has uniform transmittance and refraction in the plane direction. It is now possible to obtain the rate value.

Furthermore, in the present invention, the antireflection film is titanium oxide (T
10x), silicon oxide-titanium oxide mixture.

This ARF is formed in a metal oxide such as tantalum oxide, a transparent conductive film (tin oxide, etc.) or a metal nitride such as titanium nitride or indium nitride.
Further, in order to form a Selfaline electrode, the present invention uses electroless plating of a metal, especially a metal whose main component is nickel (boron, phosphorus, titanium, silicon, etc. may be added thereto). This electroless plating method is characterized in that the equipment is simple, mass production is easy, and material usage efficiency is extremely high.

The details are described below according to the drawings.

FIG. 2 is a vertical sectional view showing one manufacturing method of the present invention.

In FIG. 2(A), a semiconductor substrate (1), for example, a silicon semiconductor P type 0.37100 fLQm, especially 1 to 34 cm, is thoroughly cleaned on the front and back surfaces, and then thermally oxidized in an oxygen atmosphere to form silicon oxide. The coating is 1000~400OA
In particular, it was formed to have a thickness of 1500 to 250 OA without pinholes.

Furthermore, after selectively forming a resist on the periphery of the front surface and the back surface of the semiconductor (1) by a printing method on this upper surface,
Selective etching was performed to expose only the top surface of the semiconductor. Furthermore, oxide A is applied to the entire upper surface including this exposed surface.
For example, by adding RP (3) to T10x, P, O, are Ti
This is Ti Ox-8i 07, which was formed to a thickness of 700 to 100 OA after firing by an ink screen method or a coating method containing 0.1 to 10% of Ox.
7-PtOni compound ARII' may be used. In this coating method, the above-mentioned coating material manufactured by Tokyo Ohka Co., Ltd. was used, and the coating material was rotated with a spinner to control its thickness. In addition, in the screen printing method, the unevenness of the mesh of the mask is obtained by forming smooth waves, or is formed by flattening it into a planar shape.Furthermore, hydrocarbons, etc., which are binders contained in TiOx, are heated. This was then evaporated to form an antireflection film such as TiOx.

By heating and firing at a temperature of 850 to 10oO°C, the phosphorus contained in this ARP is thermally diffused into the semiconductor.
The semiconductor layer (4), which has a conductivity type opposite to that of the substrate with a sheet resistance of 1.0 to 100 fLA3, has a thickness of 0 as shown in Figure 2 (B).
．． It was formed to a thickness of 5 μm or less.

Furthermore, in FIG. 2(B), a resist film (5) is printed by a printing method or a photoetching method, particularly a printing method, using a screen mask except for the electrode window holes (8), (g). The ARP in the hole (8) and (a) is removed using an acidic etching solution, and the semiconductor layer (4) is removed.
00) and subjected to α force.

Next, after cleaning and rinsing the surface with water, 5nC1!
, HCI, and water to Sensi Tiger.
Soak for 30 minutes and soak. Furthermore, the surface was activated by immersing it in Red Schumer's solution, which is an activator, for 5 to 30 minutes. Thereafter, these were immersed in a nickel electroless plating solution (also referred to as an electroless plating solution) constituting the metal electrode, that is, Schumer V solution manufactured by Kanyan Japan. Then the semiconductor surface 00).

There is no nickel on the resist film (5) as well as on the α force.
Precipitation plating was performed to a thickness of 1 to 0.5 microns.

Furthermore, after washing this lightly with water and hot water, heat it at 100-200°
It was heated and dried at C. At this time, a similar metal film was also formed on the back surface as a back electrode (6). Furthermore, this resist was dissolved away by lightly adding nail 4 freezing with an organic solvent such as trichlene, and unnecessary metal on the upper surface was also lifted on and removed.

Thus, the external lead-out electrode hole (8) and the comb-shaped electrode hole (
8) also had the same shape as the metal electrode formed closely on the semiconductor layer, forming an electrode α-hole and an external lead-out electrode α-hole.

In the structure shown in FIG. 2(0), the ARP is adjacent to the electrode α1,0■ on its side and the entire electrode is plated in the same shape, so there is a gap between the ARP and the electrode.

In addition, there was no rise around the sides as shown in (to) in FIG. 1(C), and the effect as an antireflection film was great.

This portion of the electrode α→ is shown in an enlarged view in FIG.

That is, an electrode (2) is closely attached to the surface of the semiconductor layer (4) of the opposite conductivity type on the semiconductor (1), and an auxiliary electrode (alpha) such as a conductor (7) is further provided on the upper surface of the electrode (2). A RP (3) is provided adjacent to the lower part of the periphery of this electrode. Therefore, there is no gap at all on this side.

In the drawing, since the ARP was formed by a screen printing method, it has smooth irregularities on the surface corresponding to the mesh, but this had the effect of further lowering the reflectance because it caused the incident light to be birefringent.

This ARP had smooth irregularities and was formed in an average planar shape on the upper surface of the semiconductor, and had a practically ideal structure.

In the structure shown in FIG. 2(C) above, the conversion efficiency is 10 to 1.
8% s open circuit voltage 0.55~0.60v A M l
(100 mW/C, a). Further, even under a 3001x fluorescent light, an open circuit voltage of 7 to 9% and an open circuit voltage of 0.4 to 0.45 V could be obtained. Furthermore, this process uses the Selfa Line process and the ARP also serves as a diffusion source for impurities, making the manufacturing process extremely simple.
Even for a rectangular solar cell such as a male, the film thickness can be made uniform in the peripheral area, which is very convenient.

FIG. 4 shows another embodiment of the invention.

That is, in FIG. 4(A), the substrate semiconductor, for example, P-type 0
．． An oxide film is selectively formed on silicon of 5 to 100 μm in the same manner as in the embodiment shown in FIG. ASG) is formed at 150 to 300"C.
! Pre-bake was performed.

Next, the N
The layer was diffused to a depth of 0.5μ or less, particularly 300A-0.1μ, to form an N layer (sheet resistance 5-50"7'o) to increase the open circuit voltage. Next, all the silicon oxide on these semiconductors was fluorinated. It was removed with an acidic liquid to obtain Figure 1).

Next, ARP is applied to the top surface of this semiconductor layer (4) and semiconductor (1).
(3) is formed by screen printing method or coating method,
As in FIG. 2(B), the resist (5) is placed in the electrode window hole (8).

It was selectively formed in other parts except for (8).

Furthermore, metal films (6) and (6) were formed on the top surfaces of these by electroless plating in the same manner as in Figure 2 (B), the resist film was eluted, and the nickel film thereon was removed by lift-on. .

In this way, a photoelectric conversion device as shown in the vertical sectional view of FIG. 4(c) could be obtained. In such a structure, the conversion efficiency can be further increased by 2 to 4 times to 16 to 18 inches under AMI, and in particular, the fluorescent light T with short wavelength characteristics can be further improved.
(3001x) 7-8 chisunawachi 10-11μW/
A conversion efficiency as high as cmL could be obtained.

These values are 20-40% higher conversion efficiency than conventional photoelectric conversion devices using single-crystal silicon.Furthermore, the manufacturing process requires only one mask alignment and one impurity diffusion, resulting in lower manufacturing costs. We were able to reduce it by about 30%.

From Figures 2 and 4 (B) (In the step of moving to C, an electrode (1o) is formed on the antireflection film of the electrode part using the photoresist (7) as a mask, and then 400-'i'o
.

The electrode material may be passed through the anti-reflection film by heating at 7°C, and the silicon nitride layer (5), which is an extremely thin film thereunder, may act as a barrier. In such a case, the etching process was not necessary, and the process could be further simplified.

As is clear from the above explanation, the present invention relates to the electrode on the light irradiation surface side, and the light irradiation surface can be made thicker or thinner than other parts on the top surface, the side surface, and the side surface where the antireflection film remains. It has a uniform thickness and refractive index over the entire surface,
The incident light could be efficiently introduced into the semiconductor.

Furthermore, the present invention makes it possible to form electrodes in a simple electrolytic bath without using expensive equipment such as vacuum evaporation of aluminum, which has been conventionally used for forming electrodes. Since ohmic contact is made with the N-type semiconductor, even higher reliability can be achieved.

In the present invention, the semiconductor substrate is made of single crystal silicon.
It is applicable to photoelectric conversion devices using polycrystalline silicon such as SO, dendrite silicon, silicon processed by high-speed quenching method, or an amorphous or semi-amorphous semiconductor formed on a substrate. It goes without saying that the present invention can also be applied to other semiconductors such as germanium and compound semiconductors.

Further, the present invention has only shown a case in which one of the photoelectric conversion devices has a diode structure used in a photosensor or a solar cell. However, these methods are also effective for light-receiving elements such as phototransistors, composites, diode arrays, and image sensors, as well as light-emitting elements using compound semiconductors or non-single-crystal semiconductors. In particular, it is believed that the Selfaline method using the electroless plating method of the present invention is effective for low-temperature processing of semiconductors, particularly soft semiconductors such as amorphous, semi-amorphous semiconductors, and iv compound semiconductors.

[Brief explanation of the drawing]

FIG. 1 shows the manufacturing process of a conventional photoelectric conversion device. FIG. 2 is a vertical sectional view showing the photoelectric conversion device of the present invention and its manufacturing process. FIG. 3 shows a partially enlarged view of the photoelectric conversion device obtained in FIG. 2. FIG. 4 shows another photoelectric conversion device of the present invention and its manufacturing process. Inspection 3 figure 6' ￥4 figure

Claims (1)

[Claims] 1. - A semiconductor layer of opposite conductivity type is provided on the upper surface of a semiconductor of conductivity type, and the antireflection film provided on the semiconductor layer is identical to the electrode holes and pattern holes provided in the film. A photoelectric conversion device comprising: a metal electrode having a shape and provided in a hole in close contact with the semiconductor layer. 2. A photoelectric conversion device according to claim 1, characterized in that it is provided with a metal electrode formed by electroless plating, the main component of which is nickel. 3. In claim 1, the planar antireflection film provided on the semiconductor layer is mainly composed of titanium oxide or a mixture of titanium oxide and silicon oxide and has a refractive index of 1.7 to 2.
．． 1. A photoelectric conversion device characterized in that it is provided with: 2.