HIGH MOBILITY TOP-GATE MICRO-CRYSTALLINE SILICON TFTs PROCESSED at LOW TEMPERATURE ( < 200℃)

摘要

N type top gate microcrystalline silicon thin film transistors (TFTs) are fabricated on glass substrates at a maximum temperature of 200℃. The active layer is an undoped μc-Si film, 200 nm thick, deposited by PECVD. The drain and source regions are highly phosphorus (N-type TFTs) doped μc-films deposited also by PECVD. The gate insulator is a silicon dioxide film deposited by RF sputtering. Al-SiO_2- N type c-Si structures using this insulator present low flat-band voltage, -0.2V, and low density of states at the interface D_(it) =6,4 x 10~(10) eV~(-1)cm~(-2). High electron field effect mobility, 40 cm~2/V.s, is obtained. The sub-threshold slope is as low as 0.4 V/dec.