Predoped transfer gate for a CMOS image sensor

摘要

A novel CMOS image sensor Active Pixel Sensor (APS) cell structure and method of manufacture. Particularly, a CMOS image sensor APS cell having a predoped transfer gate is formed that avoids the variations of Vt as a result of subsequent manufacturing steps. According to the preferred embodiment of the invention, the CMOS image sensor APS cell structure includes a doped p-type pinning layer and an n-type doped gate. There is additionally provided a method of forming the CMOS image sensor APS cell having a predoped transfer gate and a doped pinning layer. The predoped transfer gate prevents part of the gate from becoming p-type doped.