Design and optimization of backside illuminated image sensor for epiretinal implants

作者：Ghormishi Mohammad Hamzeh; Karami Mohammad Azim^*

来源：Computers & Electrical Engineering, 2015, 45: 352-358.

DOI：10.1016/j.compeleceng.2014.12.007

• Epiretinal implants
• CMOS
• Image sensor
• Back side illumination

Backside illuminated pixel structure is proposed and evaluated as the building block for the image sensor being used as epiretinal prosthesis implant. The image sensor pixel is designed with the parameters of 90 nm technology node of standard CMOS (Complementary Metal Oxide Semiconductor) process. The image sensor is consisted of a p-sub/n-well structure as the photosensitive area with the pixel pitch of 20 mu m. The maximum fill factor is observed due to separation of photosensitive area with the readout transistor surface in backside illumination technology. 90% quantum efficiency at 600 nm wavelength and the dark current of 74.6 nA/cm(2) at room temperature is achieved for the optimized pixel. The application of deep backside Deep Trench Isolation (DTI), with high depth n-well doping profiles, results in a significant reduction of crosstalk (5.6% total crosstalk).

• 出版日期2015-7