Implementation of Eye-Safe Imaging Capability onto CMOS Image Sensors with Reverse-Carrier-Injection

Abstract

We propose Si-CMOS image sensors that can detect near infrared (NIR) light, including the eye-safe region (λ: 1.4-2.0μm). The capability of the sensor to capture visible images remained completely intact. The proposed sensor consisted of a conventional Si complementary metal oxide semiconductor (CMOS) image sensor and a Ge photodiode (PD) array formed underneath a CMOS image sensor. The operation principle for NIR detection was based on photo-carrier injection into the Si-substrate from the Ge PD. A process to form n-regions on the reverse of a fabricated CMOS sensor is also discussed.