Design and Properties of Low noise Silicon Avalanche photodiode

The avalanche photodiode in a standard CMOS technology is designed by using TCAD tool, a simulation tool for fabrication process and also electrical performances. This paper proposed a planar Si-Avalanche Photodiode with presence of guard ring. An efficient guard ring structure is created to prevent breakdown at the edges. It is operated in reverse bias which means by using SILVACO ATLAS, the anode connected to the negative terminal and ground to the cathode in fabrication. The paper includes the effect and relationship of avalanche photodiode between substrate concentrations and doping, type of materials, with the breakdown voltage were investigated [1]. Then, the structure is applied with guard ring structure. At the end, we choose the best optimized design of avalanche photodiode based on current-voltage characteristics. The main electro optical characteristics of the device are presented such as responsivity, dark current, absorption etc. Simulation of device at different reverse voltages shows us a very low dark current and conveys vital information about absorption that it does not depends upon reverse voltage.