Method of making a TFT having a reduced channel length

摘要

A thin film transistor (TFT) for a liquid crystal display (LCD) and method of making same is disclosed, the TFT having a source and drain electrode where at least one of the source and drain includes first and second conductive layers offset from one another by a distance DELTA L so that the resulting TFT channel length LT is equal to LT=L1,2- DELTA L where L1,2 is either a channel length defined in the first conductive layer or a channel length defined in the second conductive layer. The TFT manufacturing process includes the steps of: a) providing a conductive gate layer and patterning same to form a gate electrode; b) depositing a substantially transparent conductive layer (e.g. ITO) and patterning same to form a pixel electrode; c) depositing and patterning a semiconductor layer (e.g. a-Si); a doped semiconductor contact layer; and a first source-drain conductive layer so as to form a TFT island or area; d) using a single photoresist to etch a channel in the first source-drain layer and a via in a gate insulating layer so as to expose the pixel electrode; and e) depositing and patterning a second source-drain layer over the via and the etched first source-drain layer so as to form a TFT with reduced channel length LT wherein the second source-drain layer contacts the pixel electrode through the via.