1. A novel pixel design with hybrid type isolation scheme for low dark current in CMOS image sensor
- Author
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Hyung Jun Han, Sang Il Jung, Young Heub Jang, Ho Woo Park, Jeong Jin Cho, Yonghan Roh, Jung Chak Ahn, Min Seok Oh, Hiroshige Goto, Chi-Young Choi, Yi Tae Kim, Hoon Oh, Sung-Ho Choi, Jong-Won Choi, and Young-Hwan Park
- Subjects
Physics ,CMOS sensor ,Pixel ,business.industry ,Transistor ,Dot pitch ,Photodiode ,law.invention ,law ,Shallow trench isolation ,Optoelectronics ,Image sensor ,business ,Dark current - Abstract
New isolation scheme for CMOS image sensor pixel is proposed and its improved dark current performance is reported. It is well known that shallow trench isolation (STI) is one of major sources of dark current in imager pixel due to the existence of interfacial defects at STI/Si interface. On the account STI-free structure over the whole pixel area was previously reported for reducing dark current. As the size of pixel pitch is shrunk, however, it becomes increasingly difficult to isolate in-pixel transistors electrically without STI. In this work, we implemented hybrid type isolation scheme of removing STI around photodiode to suppress the dark current and remaining STI near transistors to guarantee the electrical isolation of transistors in pixel. It was successfully achieved that the dark current was significantly reduced by removing the STI around the photodiode together with normal operation of in-pixel transistors.
- Published
- 2013
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