Semiconductor device for driving a substrate of an electro-optical device

Abstract

A semiconductor device includes an insulating substrate; a plurality of pixel electrodes arranged in a matrix on the insulating substrate; first thin film transistors for individually driving the pixel electrodes; and driving circuits composed of second thin film transistors formed on the insulating substrate. In this semiconductor device, each of the first and second thin film transistors has a bottom-gate structure comprising a gate electrode patterned on the insulating substrate; a gate insulating film covering the gate electrode; and a semiconducting thin film having a channel region and a source/drain region, which is formed on the gate insulating film. Each of the second thin film transistors has a lightly doped region at least between a drain side highly doped region and the channel region. The lightly doped region mitigates an electric field concentration at a drain edge and hence suppresses harmful charges generated both in an interlayer insulating film and in the gate insulating film which are respectively brought in contact with upper and lower sides of the semiconducting thin film.