JPH06836Y2 - Solar cell type diode - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention is used, for example, in a solar cell array that supplies electric power to a spacecraft such as an artificial satellite, by mounting it on an array substrate as a blocking diode or a shunt diode. The present invention relates to a solar cell type diode.

<Outline of the Invention> A solar cell type diode having the same shape as a solar cell, that is, a wafer, and a PN junction functioning as a diode is formed on the surface of the wafer, and electrodes are provided on the upper surface of the junction and the back surface of the chip. In order to operate this normally as a blocking diode or a shunt diode, it is necessary to completely block the incidence of light from the outside and prevent the generation of photovoltaic power in the diode. Therefore, by attaching a metal film having a high reflectance to sunlight on one main surface and attaching this glass to the diode chip with an adhesive, it is possible to use the glass without damaging the emissivity of the glass and to the diode. It is possible to block the incidence of sunlight and reduce the ratio of solar absorptance to emissivity, which enables operation at a low temperature that is generally preferable for semiconductor devices.

<Prior Art> Conventionally, an electrode is provided on the entire surface of the diode chip to shield light. Also, a cover glass has been adhered to improve the thermal characteristics.

<Problems to be Solved by the Invention> However, since the solar cell type diode is used by being mounted on the solar cell array substrate similarly to the solar cell, the solar cell type diode is irradiated with sunlight like the solar cell. If the light shielding to the diode is insufficient, a photovoltaic power is generated by the PN junction of the diode, and in the case of a blocking diode, it acts to cancel the generated voltage of the solar cell array, and in the case of a shunt diode, the generation of the solar cell array. Since the voltage is shunted by the voltage of both terminals of the diode, the original generated power is significantly lost. Therefore, if an electrode is to be provided on the entire surface of the diode in order to block light from entering the diode, it is necessary to devise a means for preventing a short circuit in both P and N regions.

<Means for Solving Problems> A diode chip and a glass having a metal film having a high reflectance for sunlight on one main surface are attached, and the glass has a diode chip with respect to the diode chip. It is characterized in that the metal film of the glass is adhered to the surface of the diode chip via an adhesive so as to face the surface of the diode chip.

<Operation> According to the present invention, with the above-described structure, if an adhesive layer such as an adhesive layer is formed between the diode chip surface and the metal film, the diode can be easily formed without short-circuiting the P region and the N region. It is possible to prevent light from entering the chip. In addition, since the emissivity from the glass surface is not lost, the high emissivity of the glass is maintained, and it is possible to reduce the solar absorptance to emissivity ratio of the diode as well as to prevent the incidence of light on the metal film surface. Therefore, the operating temperature of the diode can be lowered.

<Embodiment> An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a solar cell diode according to an embodiment of the present invention.

1 is glass, 2 is a metal film, 3 is an N-type silicon substrate, 4 is a P-type diffusion layer, 5 is a P electrode, 6 is an N electrode, 7 is a diode chip, 8 is a thin film lead, and 9 is an adhesive. .

In this embodiment, as shown in the drawing, a metal film 2 having a high reflectance for sunlight is attached to one main surface of the glass 1, and the glass 1 is attached to the surface of a diode chip 7. ing.

A method of manufacturing the solar cell type diode having the above structure will be described.

First, a P-type impurity such as boron is diffused in the N-type silicon substrate 3 to form a P-type diffusion layer 4, and mesa etching is performed.
A PN junction that functions as a diode is formed on the surface of the substrate 3. After that, the P electrode 5 and the N electrode 6 are formed, and the diode chip 7 is manufactured. In addition, the diode chip 7
A thin plate-shaped lead 8 is attached to the P electrode 5 on the front surface side of, by welding or the like. On the other hand, to the extent that sunlight does not pass through a metal film 2 having a good reflectance for sunlight such as aluminum on one main surface of the glass 1 having a thickness of, for example, about 50 to 500 microns by a vacuum deposition method or the like. To the thickness of. The surface to which the metal film 2 such as aluminum is attached is
The surface of the diode chip 7 is adhered by using an adhesive 9 such as a silicone resin.

In the illustrated example, a mesa type diode is used, but the present invention can also be applied to a planar type diode.

In the present invention, the metal film attached to one main surface of the glass blocks the incidence of sunlight, so when used as a blocking diode or a shunt diode in a solar cell array, the photocurrent that adversely affects the operation of the array is prevented. Occurrence can be prevented. Moreover, since almost all of the sun is reflected from the metal film surface, the so-called solar absorptivity can be suppressed to a very low level, and good thermal emissivity, which is a preferable characteristic of glass, is maintained, so the solar absorptivity is The emissivity to heat becomes small, and it becomes possible to keep the operating temperature of the diode low.

<Effects of the Invention> As described above, according to the present invention, with a simple structure,
By blocking the incidence of light from the outside, it prevents the generation of photocurrent, and also blocks the conduction of heat from the outside.
It is possible to provide a new useful solar cell type diode capable of releasing the heat generated by the diode to the space by being diffused from the glass.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a solar cell diode according to an embodiment of the present invention. 1 ... Glass, 2 ... Metal film, 7 ... Diode chip, 9 ...
adhesive.

Claims (1)

[Scope of utility model registration request] 1. A diode chip, and a glass having a metal film having a high reflectance for sunlight on one main surface, the glass being bonded to the diode chip with an adhesive. A solar cell type diode, characterized in that the metal film of the glass is bonded so as to face the surface of the diode chip.