P-1: A Novel Self-Aligned Etch Stopper Structure with Lower Photo Leakage for AMLCD Applications

Abstract

We introduce a novel self‐aligned etch stopper, sidewall‐contact a‐Si:H TFT (ESSC‐TFT) which allow us to reduce the photo leakage current by the island‐in structure. This ESSC‐TFT design reduces the volume of a‐Si film, the active region can totally be shielded by the gate metal resulting in the prevention from direct back light illumination. With the sidewall‐contact, the hole current is reduced due to the smaller contact area, and we expect the source, drain parasitic intrinsic resistance of a‐Si can be also lessened by the ESSC‐TFT structure. Although the defects between etched a‐Si and n+ a‐Si film may degrade the on current, the ESSC‐TFT still exhibits higher on‐off ratio than the one in traditional ES‐TFT structure.