Rohm Co., Ltd.

National Institute of Advanced Industrial Science and Technology

Kenichi Miyazaki

Osamu Matsushima

Shigeru Niki

Shogo Ishizuka

Keiichiro Sakurai

Masaki Takaoka

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 light-absorbing layer is composed of a compound-semiconductor film of chalcopyrite structure, a surface layer is disposed on the light-absorbing layer, the surface layer having a higher band gap energy than the compound-semiconductor film, an upper electrode layer is disposed on the surface layer, and a lower electrode layer is disposed on a backside of the light-absorbing layer in opposition to the upper electrode layer, the upper electrode layer and the lower electrode layer having a reverse bias voltage applied in between to detect electric charges produced by photoelectric conversion in the compound-semiconductor film, as electric charges due to photoelectric conversion are multiplied by impact ionization, while the multiplication by impact ionization of electric charges is induced by application of a high-intensity electric field to a semiconductor of chalcopyrite structure, allowing for an improved dark-current property, and an enhanced efficiency even in detection of low illumination intensities, with an enhanced S/N ratio.

Method of fabricating photodiode

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

A fabrication method for solid-state imaging devices includes having circuitry formed on a substrate, forming a lower electrode layer on the circuitry, patterning the lower electrode layer to separate pixel-wise into a set of segments, and forming a compound-semiconductor film of chalcopyrite structure over a whole area of element regions. A resist layer is applied on the compound-semiconductor thin film to pixel-wise pattern in accordance with the lower electrode layer as a base separated into the set of segments, and an ion doping is applied over a whole area of element regions, forming element separating regions in the compound-semiconductor thin film. The method includes removing the resist layer for exposure of surfaces of as set of compound-semiconductor thin films separated pixel-wise by the element separating regions. A transparent electrode layer is formed in a planarizing manner over a whole area of element regions.

Solid-state imaging device and fabrication method thereof

Photodiode and method of fabricating photodiode

Provision of a solid-state imaging device of a planarized structure with reduced dark currents, allowing for high sensitivities over a wide wavelength band ranging from visible wavelengths to near-infrared wavelengths, and a fabrication method of the same. There are steps of having circuitry () formed on a substrate (), forming a lower electrode layer () on the circuitry (), patterning the lower electrode layer () to separate pixel-wise into a set of segments, forming a compound-semiconductor thin film of chalcopyrite structure () over a whole area of element regions, applying a resist layer () on the compound-semiconductor thin film () to pixel-wise pattern in accordance with the lower electrode layer () as a base separated into the set of segments, applying an ion doping over a whole area of element regions, forming element separating regions () in the compound-semiconductor thin film (), removing the resist layer () for exposure of surfaces of a set of compound-semiconductor thin films () pixel-wise separated by the element separating regions (), and forming a transparent electrode layer () in a planarizing manner over a whole area of element regions.

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.

Growing community of inventors

Kyoto-fu, Japan

Kenichi Miyazaki