AN AMORPHOUS-SILICON TFT WITH ANNULAR-SHAPED CHANNEL AND REDUCED GATE-SOURCE CAPACITANCE

An amorphous silicon Thin-Film Transistor (a-Si TFT) with an annular-s haped channel is presented, The Annular-Channel TFT (AC-TFT) is fabric ated using standard design rules with 4 mu m minimum feature size whic h is common in large area applications such as Active Matrix LCD's. Th e AC-TFT has two times smaller gate-to-source capacitance of about 50 fF in the on-state as compared to a conventional Rectangular-Channel T FT (RC-TFT) which has the same on-current of more than 10 mu A at V-gs = 20 V and V-ds = 10 V, Its off-current under illumination from the g ate side is about ten times lower than that of the RC-TFT.