[Invited Paper] High Sensitivity Crystalline Selenium-based CMOS Image Sensor Using Avalanche Multiplication

Abstract

We present our work on a complementary metal oxide semiconductor (CMOS) image sensor that uses crystalline selenium as the photoconversion layer and enables avalanche multiplication at low voltage, with the goal of realizing a high-definition, high-sensitivity camera. Gallium oxide, used as a hole blocking layer, and nickel oxide used as an electron blocking layer effectively prevents the increase of external dark current caused by carrier injection from an external electrode. In addition, a new crystallization method was developed to improve the crystallinity of selenium for the fabrication of crystalline selenium films. We were able to capture high-quality images in a crystalline selenium-based CMOS image sensor and confirm signal amplification by a factor of approximately 1.4 at a reverse bias voltage of 22.6 V by using these film structures and deposition conditions.