Effects of high-pressure annealing on random telegraph signal noise characteristic of source follower block in CMOS image sensor

Abstract

The effect of high-pressure deuterium (D) and hydrogen (H) annealing on random telegraph signal (RTS) noise characteristics of source follower (SF) block, SF, and row selector (SEL) transistors in CMOS image sensor (CIS) active pixel sensor (APS) was comparatively analyzed in depth. RTS noise characteristics of SF transistor (M1) and SEL transistor (M2) with forming gas (FG) annealing showed the smallest Delta I-D/I-D, whereas FG annealing was not efficient to reduce the RTS noise of SF block (M1 + M2). Although Delta I-D/I-D of SF block was reduced by high-pressure H-2 annealing, high-pressure D-2 annealing showed the greatest reduction in Delta I-D/I-D of SF block (M1 + M2), which was believed to attribute to the effective passivation of interface traps by the isotope effect of D. Therefore, high-pressure D-2 annealing is potentially significant for reducing RTS noise characteristics and thermal budget as well as improving device performance in CIS APS.