CMOS Image Sensor Overlaid with a HARP Photoconversion Layer

Abstract

Aiming at highly sensitive solid-state imager we developed a new CMOS image sensor, which was made by connecting an avalanche photoconversion layer (HARP film) to a CMOS readout circuit. A prototype sensor was fabricated through 2um CMOS technology, which employed 0.4-um-thickHARP film, new MOS FET structure capable of increasing endurance voltage in the readout circuit, and indium micro-bump electrode formed with two layer photoresist process. Signal current multiplication of about 5 times and its stable operation were observed when applying a target voltage of 60V.