National Institute of Advanced Industrial Science and Technology

Rohm Co., Ltd.

Keiichiro Sakurai

Shigeru Niki

Shogo Ishizuka

Osamu Matsushima

Kenichi Miyazaki

Koji Matsubara

Akimasa Yamada

Masaki Takaoka

Hajime Shibata

Hitoshi Tampo

A solid state imaging device includes a circuit unit formed on a substrate and a photoelectric conversion unit. The photoelectric conversion circuit includes a lower electrode layer placed on the circuit unit, a compound semiconductor thin film of chalcopyrite structure which is placed on the lower electrode layer and functions as an optical absorption layer, and an optical transparent electrode layer placed on the compound semiconductor thin film. The lower electrode layer, the compound semiconductor thin film, and the optical transparent electrode layer are laminated one after another on the circuit unit.

Solid state imaging device and fabrication method for the same

A photoelectric conversion device has a high S/N ratio and can increase the detection efficiency even under a low luminance. The photoelectric conversion device generates an increased electric charge by impact ionization in a photoelectric conversion unit formed from a chalcopyrite type semiconductor, so as to improve dark current characteristic. The photoelectric conversion device includes: a lower electrode layer; a compound semiconductor thin film of chalcopyrite structure disposed on the lower electrode layer and having a high resistivity layer on a surface; and a transparent electrode layer disposed on the compound semiconductor thin film , wherein the lower electrode layer, the compound semiconductor thin film, and the transparent electrode layer are laminated one after another, and a reverse bias voltage is applied between the transparent electrode layer and the lower electrode layer, and the multiplication by the impact ionization of the electric charge generated by photoelectric conversion is generated within the compound semiconductor thin film. It is also possible to provide a fabrication method for such photoelectric conversion device, and a solid state imaging device using the photoelectric conversion device.

Photoelectric conversion device, fabrication method for the same, and solid state imaging device

An object of the present invention is to increase the light emission efficiency of a ZnO-based optical semiconductor device. An optical semiconductor device B has a structure which includes n-type ZnMgO (barrier layer)/ZnMgO (active layer)/p-type ZnMgO (barrier layer), and light is emitted from the active layer. Electrodesare respectively formed on barrier layers. By applying a voltage between the two electrodes, light is emitted from ZnO (active layer). Here, there are a relationship of x&#x3c;y and a relationship of x&#x3c;z. For instance, such values as x=0.1, y=0.15 and z=0.16 can be chosen. Otherwise, such values as x=0.15, y=0.25 and z=0.24 can be choose as well. In this case, by increasing the value x of the active layer, it is possible to shift its light emission wavelength to the shorter wavelength side. In addition, as shown in the above-described results, by increasing the value x, it is possible to enhance its light emission efficiency. For this reason, the optical semiconductor device is excellent as a light-emitting device.

Semiconductor device

A solid state imaging device with an easy structure in which have the high sensitivity which reaches the wide wavelength region from visible light to near infrared light wavelength region, and dark current is reduced, and a fabrication method for the same, are provided. A solid state imaging device and a fabrication method for the same, the solid state imaging device comprising: a circuit unit formed on a substrate; and a photoelectric conversion unit including a lower electrode layer placed on the circuit unit, a compound semiconductor thin film of chalcopyrite structure which is placed on the lower electrode layer and functions as an optical absorption layer, and an optical transparent electrode layer placed on the compound semiconductor thin film, wherein the lower electrode layer, the compound semiconductor thin film, and the optical transparent electrode layer are laminated one after another on the circuit unit.

A method for producing a semiconductor film having a chalcopyrite structure including a Ib group element, a IIIb group element and a VIb group element including selenium, the method including cracking selenium with plasma to generate radical selenium, and using the radical selenium in the process of forming the semiconductor film.

Growing community of inventors

Ibaraki, Japan

Keiichiro Sakurai