Title :
Air-gap guard ring for pixel sensitivity and crosstalk improvement in deep sub-micron CMOS image sensor
Author :
Dun-Nian Yaung ; Shou-Gwo Wuu ; Ho-Ching Chien ; Tzu-Hsuan Hsu ; Chien-Hsien Tseng ; Jeng-Shyan Lin ; Jieh-Jang Chen ; Chin-Hsin Lo ; Chung-Yi Yu ; Chia-Shiung Tsai ; Wang, C.S.
Author_Institution :
Taiwan Semicond. Manuf. Co., Hsin-Chu, Taiwan
Abstract :
An air-gap guard ring around the pixel sensor, to improve pixel sensitivity and crosstalk, in 0.18 /spl mu/m CMOS image sensor technology has been successfully developed. By using the RI (refractive index) difference between the air gap (RI/spl sim/1) and dielectric films (RI=1.4/spl sim/1.6), the major incident light is collected in the targeted pixel due to the total internal reflection occurred in the air-gap/dielectric-film interface. The small pixel pitch of 2.8 /spl mu/m/spl sim/4.0 /spl mu/m has been characterized and demonstrates excellent optical performance. For a 3.0 /spl mu/m pixel, the pixel sensitivity shows 45% enhancement and optical spatial crosstalk achieves 90% reduction at 20/spl deg/ incident angle.
Keywords :
CMOS image sensors; light reflection; optical crosstalk; refractive index; 0.18 micron; 2.8 to 4.0 micron; 3.0 micron; CMOS image sensor; air-gap pixel guard ring; air-gap/dielectric-film interface; light incident angle; optical spatial crosstalk; pixel crosstalk improvement; pixel sensitivity improvement; pixel sensor; refractive index; total internal reflection; Air gaps; CMOS image sensors; CMOS technology; Optical crosstalk; Optical films; Optical refraction; Optical sensors; Optical variables control; Pixel; Refractive index;
Conference_Titel :
Electron Devices Meeting, 2003. IEDM '03 Technical Digest. IEEE International
Conference_Location :
Washington, DC, USA
Print_ISBN :
0-7803-7872-5
DOI :
10.1109/IEDM.2003.1269308
