CMOS Image Sensor with Lock-In Pixels for Biomedical Applications

This paper presents an overview of the technique to achieve fast charge transfer time in CMOS image sensors (CIS) for the biomedical applications. The CIS uses lock-in pixel based on lateral electric field charge modulator (LEFM). The lock-in pixels have been realized as two-tap and four-tap structures with a charge transfer time of less than 4 ns for the large pixel and less than 400 ps for the small pixel, which can be used to achieve lock-in functions and time-resolved imaging. The applications using the implemented CIS in stimulated Raman scattering (SRS) and near-infrared spectroscopy (NIRS) have been demonstrated. Both applications utilized near-infrared laser between 700 nm to 800 nm and were fabricated using a 0.11 μm CIS process.