JPS6174376A - Thin-film photovoltaic element - Google Patents

Abstract

PURPOSE:To protect lower layers from damage in a process of isolating upper layers by a method wherein the isolating regions for semiconductor thin films and second electrodes are positioned, respectively, on the regions of first electrodes and semiconductor thin films that are located just under them, in a plurality of photovoltaic regions composed of first electrodes, semiconductor thin films, and second electrodes, deposited in that order. CONSTITUTION:When an a-Si layer is patterned on metal electrodes 21, 22, 23, 24, isolating regions 71, 72 between a-Si layer regions 31, 32, 33 are positioned just over the electrodes 22, 23 of solar battery cells 20, 30. Isolating regions 73, 74 between transparent electrodes 41, 42, 43 formed by the patterning of a transparent electrode layer are also caused to be positioned over the layers 32, 33 of the solar battery cells 20, 30. Consequently, the process of laser beam application is accomplished only on the metal electrodes and semiconductor thin films that are free of steps, protecting the substrate 1 and metal electrode layers.

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

In the present invention, yCII! The present invention relates to a thin film photovoltaic device, such as an amorphous silicon (hereinafter referred to as a-S+) solar cell, which has a plurality of photovoltaic power generating regions.

[Prior art and its problems]

Figure 2 shows an example of a conventional A-5L solar cell, in which three metal electrodes are mounted on an absolute substrate such as a polymer film such as a borimide film, a stainless steel plate coated with a heat-resistant resin, or a ceramic plate. 21, 22.23 are deposited, and a-5tall 31.32133 and transparent electrode@41, 42.43 are further laminated on top of each other, thereby forming three tanzakubo solar cells 10.20.30. is configured. In each cell, an extension of the transparent electrode Pi 41 is a metal electrode 22.
The extension of the transparent electrode 42 contacts the metal electrode 23 to connect them in series, and the output can be taken out from the extension of the metal electrode 21 and the transparent electrode 43. Such a solar cell is manufactured through the steps shown in FIG. A metal M2 is formed on the substrate 1 to a thickness of about 1 μm. The metal layer is A1. ↑s * Cr +! 1 o + Single layer stainless steel alloy is ^l/T1. ^L/It consists of a 2N film made of stainless steel, etc., and is deposited by vapor deposition or sputtering (Figure a).Next, unnecessary parts of the metal layer 2 are evaporated by irradiation with a YAG laser beam of approximately IW, for example. Then, using a mixed gas of silane (SiH#) and diborane (B*I1m), a p-type a- 5k layer, about o,s'tr using silane
- about 500 n-type a-st using silane and phosphine (PTIff) undoped 5T layer of thickness
m is laminated by glow discharge decomposition to form a-5t layer 3 (Figure 0).Next, a-3IJi3 is patterned using an Ar laser (0.48μ) with an irradiation power of about 1.5W. a-31 layer 3 into three areas 31.3
2. Separate into 81 parts (Figure d). Finally, a transparent electrode layer 4 made of ITO, Sn0g, etc.
No electron and -L vapor deposition to a thickness of 0.00 people. Deposited by sputtering (Fig. 0), and Ar
Transparent electrodes 41, 42, and 43 are formed by irradiating with a laser beam and performing sheet buttering (Fig. f). However, in this manufacturing process, layers below the layer to be patterned may be damaged by laser beam irradiation.

[When patterning layer 3, since the base layer 1 is sensitive to laser beam irradiation, the a-51 layer is directly attached to the part provided on the substrate, that is, the separated part of the metal electrodes 21, 22, and 23. In order to process a part that has been removed, it is necessary to lower the beam output, but this causes the patterning speed to drop to the @ end. Moreover, this output adjustment is difficult in actual practice because the spacing between the a-5L layers 31, 32, and 33 is narrow at about 0.51. Between the electrodes 23, the substrate 1, which has already been irradiated with the laser during the patterning of the metal electrode J112, is irradiated again with the laser, so that the dV! Scratch 51 as shown in J
．． 52 enters. Such scratches become mechanical and thermal weaknesses of the substrate 1 when the solar cell is used, and may cause destruction of the substrate, especially when a brittle material such as ceramic or glass is used. When the transparent electrode layer 4 is patterned on the open collar, scratches 61 and 62 are often formed on the metal electrode portion as shown in figure f, which poses a problem of increasing the series resistance of the cell. Such problems occur not only in laser separation processing but also in plasma etching or chemical reaction etching. [Object of the Invention] The present invention aims to solve the above-mentioned problems and provide a thin film photovoltaic device in which the lower layer surface is not damaged during separation processing of the upper layer. ] The present invention is directed to the -is layer stacked in order on the same insulating substrate,
In a device that has a plurality of photovoltaic force generation regions consisting of a semiconductor fit film and a second electrode, and each region is interconnected, the separation portion of the semiconductor thin film and the second electrode is connected to the first electrode and the semiconductor thin film, respectively. Achieving the above objective by being located only on top of the area 6. The isolation part is formed only on the layer directly below, so that processing can only be carried out on top of the layer directly below it, increasing the strength of processing. There is no need for minute adjustments,
Furthermore, since it does not act on the surface of the outer layer on the lower side, no damage occurs. Embodiment of the Invention FIG. 1 shows an embodiment of the present invention in an a-51 solar cell having the same configuration as shown in FIGS. 2 and 3,
Second. Components common to those in FIG. 3 are given the same reference numerals. In this case, metal electrodes 21, 22, 23.24 are formed by patterning the metal electrode layer, and fQ a -5iJ of the patterning of the a-5t layer laminated thereon.
i tit area 31.32.33 (separation part between D 71.7
2 is placed above the metal electrode 22.23 of the solar cell 20.30. For this reason, processing by Ar laser beam irradiation with a power of about 1.5 W is performed only on the metal electrode with no steps, and since the beam does not reach the substrate 1, the primary transparent electrode layer does not damage the substrate. Transparent electrodes 41.42.4 formed by patterning
Separation portion 73.74 between cell 20.30 and a-5,
i-layer 32.33. It was made to be on top of the gold 5
This separation part 71° to be originally processed will not cause any damage to the stain and will not cause a decrease in fill factor due to an increase in series resistance in cell characteristics. 2.7
3.7441 Since it is formed on a surface with no steps, the processing speed of patterning is improved and the gap can be reduced by 0.3 ms. If, following the patterning of the second transparent electrode layer, the irradiation bar is lowered and separation bands 81.82 shown by dotted lines are formed on the a-5i layer in the same pattern as the separation parts 73.74, the leakage current can be easily reduced. but! It will be done. The output of this solar battery can be taken out from the exposed portions of the metal electrode layers 21 and 24. FIG. 4 shows another embodiment, in which parts common to the previous figures are given the same reference numerals. In this case, glass substrate 1
This is a series-connected solar cell formed on 1. The structure of this solar cell is that transparent electrode layers 41, 42, 4 and 4 are provided on substrate 11.
3, a-5l' 1131, 32, 33 and 35, and metal electrode layers 21, 22, 23 and 25 are laminated in this order. The separation part 71.72 of the a-5i layer 31.32.33 is on the transparent electrode layer 42.43 of the cell 20.30, and the separation part 75.76 between the transparent electrode layers 21, 22.23 is on the cell 20. ．．
The glass substrate 11 is scratched in the gap between the patterns of the a-3i layers, and the transparent electrode layer is placed on top of the layers 32 and 33 of the metal electrode layer. Note that in order to form the metal electrode layer 25 and the a-3i layer 35 for the output extraction terminal, separation parts 78 and 77 are formed in the metal electrode layer and the a-81 layer, respectively. In this case, following the processing of the metal electrode layer, a −
By processing the separation bands 81, 82, and 83 of the 5i layer, the leakage current of the cell characteristics can be reduced. Effects of the Invention The present invention provides a semiconductor y
In a device with multiple photovoltaic power generating regions formed by an I film, the separation part of each layer between the regions is formed only on the surface of the layer directly below, and there is no step on the separation processing surface. As a result, processing accuracy is improved, and the processing does not affect layers other than those directly below it. Also, since it is easy to determine the processing conditions, it is possible to avoid damaging the layers immediately below, and separation processing improves the characteristics of the element. will not cause any harm. The processing method of the present invention is not limited to the above-mentioned laser processing, but can also be applied to processing using a chemical reaction or plasma etching method. The effect is extremely large.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an a-3i solar cell according to an embodiment of the present invention, FIG. FIG. 2 is a sectional view showing the solar cell manufacturing process, and FIG. 4 is a sectional view of another embodiment. l, 11: Insulating substrate, 21, 22, 23: Metal electrode, 3
1°32.33: a-51 layer, 41.42.43
:Transparent electrode layer, 71°72.73.74.75.76
+ Separation section, 10.20.30: Solar cell. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1) A device having a plurality of photovoltaic power generating regions consisting of a first electrode, a semiconductor thin film, and a second electrode stacked in order on the same insulating substrate, and each region is interconnected. , a thin film photovoltaic device characterized in that the separation portions of the semiconductor thin film and the second electrode are located only on the regions of the first electrode and the semiconductor thin film, respectively. 2) A thin film photovoltaic device according to claim 1, characterized in that the semiconductor thin film immediately below the separation portion of the second electrode is removed.