JPH03159180A - Optical semiconductor device - Google Patents

Abstract

PURPOSE:To obtain excellent noise resistance having an excellent shielding effect by adding a layer for transmitting a light on the surface of a photoelectric converter, leading an electrode wiring from the layer, and connecting its potential to a ground potential. CONSTITUTION:In an only a photoelectric convertor 6 or an optical semiconductor device having the converter 6 integrated with an amplifier, a layer 7 for transmitting a light to the PN junction surface of the converter 6 is added to the entire surface, an electrode wiring is led from the layer 7, and its potential is connected to a ground potential. For example, N-type region 5 is formed on a P-type substrate 4, a photoelectric converter 4 is formed, and a shielding layer 7 is added in a stripe state to the converter 6. The width of the stripe is 100mum, a region having no stripe is 200mum, an electrode wiring is led from the layer 7, connected to an outer lead via an Au wire, etc., and connected to a ground potential. The layer 7 is formed of an sp layer of a layer for transmitting a light to provide 90% of transmittance to an infrared ray.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an optical semiconductor device in which only a photoelectric conversion section or a photoelectric conversion section and an amplifier circuit section are integrated, and the surface of the photoelectric conversion section is connected to a ground potential. The present invention provides an industrial optical semiconductor device that requires noise resistance by attaching a layer to the entire surface or a part thereof to provide a shielding effect.

Conventional technology When optical semiconductors are used in industrial equipment that requires noise resistance, the optical semiconductor device 1 has been used as shown in Fig. 3.
The surrounding area is surrounded by a material such as a metal plate 2 or a conductive film, and the structure is connected to ground potential to provide a shielding effect. In such a structure, it is necessary to provide an opening 3 in the area of the photoelectric conversion section, which has the disadvantage that ambient noise is easily received through this opening.

Problems to be Solved by the Invention In the conventional structure that provides a shielding effect, it is necessary to separately attach a conductive material around the optical semiconductor device, which poses a problem in that it is laborious and costly to install. Also,
Since it is necessary to provide an opening in the area of the photoelectric conversion section, there is a problem in that it is difficult to improve noise resistance.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention adds a new shield layer that transmits light to the surface of the photoelectric conversion section of an optical semiconductor device, and connects electrode wiring from that layer. It has a new structure that greatly improves the shielding effect by drawing out the wire and connecting its potential to ground potential.

Function: According to the new shield structure of the present invention, since the shield layer is attached directly to the chip surface of the photoelectric conversion section, there is no need for shielding in the subsequent process, and by using a layer that transmits light, it is possible to form an opening like a metal plate. By connecting the potential of the shield layer to the ground potential, noise resistance can be greatly improved.

Embodiment An embodiment according to the present invention is shown in FIG. (a) shows a cross-sectional view of the vicinity of the photoelectric conversion section of the present semiconductor device, and (b) shows a plan view. An N-type region 5 is formed on a P-type substrate 4 to constitute a photoelectric conversion section 6 . Since the photoelectric conversion section 6 usually has an exposed epitaxial layer and is connected to the input of the circuit, there is a problem that common mode noise tends to cause malfunction. In the present invention, a shield layer 7 is newly attached to the surface of the photoelectric conversion section 6 in the form of a stripe. The stripe width is 100 μm, and the area without stripes is 200 μm. Electrode wiring is drawn out from this shield layer and connected to an external lead portion with an Au wire or the like and connected to ground potential. The shield layer is formed of an SP layer that transmits light, and in this example, it has a transmittance of 90% for infrared light, so the shielding effect is greatly improved without reducing photosensitivity. I'm letting you do it.

FIG. 2 shows a plan view of a chip as another embodiment of the present invention. The photoelectric conversion section is provided with a shield layer 7 over the entire surface, and the shield layer is connected to the ground potential. This embodiment uses an integrated circuit chip 9 in which a photoelectric conversion section 6 and an amplifier circuit section 8 are attached in one chip, and after wire connection is made to a lead frame, the periphery is sealed with transparent resin. It has the configuration of a semiconductor device.

Effects of the Invention As shown in the present invention, by attaching a shield layer to a part or the entire surface of the photoelectric conversion part and connecting it to the ground potential, an optical semiconductor device with excellent shielding effect and good noise resistance is provided. can do. With such a method, it is possible to easily realize a device that does not malfunction.

[Brief explanation of the drawing]

FIG. 1 shows one embodiment of the present invention, (a) is a cross-sectional view of a photoelectric conversion section, (b) is a plan view, FIG. 2 is a plan view showing another embodiment of the present invention, and FIG. The figure is a sectional view showing a conventional optical semiconductor device. 4...P-type substrate, 5...N-type region, 6
. . . Photoelectric conversion section, 7 . . . Shield layer.

Claims (2)

[Claims] (1) In an optical semiconductor device in which only a photoelectric conversion section or a photoelectric conversion section and an amplifier circuit section are integrated, a layer that transmits light is attached to the entire surface of the PN junction surface of the photoelectric conversion section, and an electrode is formed from the layer. An optical semiconductor device characterized by drawing out wiring and connecting its potential to ground potential. (2) An optical semiconductor device characterized in that a stripe-like, mesh-like, or radial layer is attached to a part of the surface of the PN junction of the photoelectric conversion part and connected to a ground potential.