Process for producing thin-film transistor

Claim 1

A process for producing a thin-film transistor comprising a first step for forming a gate electrode on an insulating substrate, a second step for continuously depositing on said gate electrode and substrate a gate insulating film, a high-resistivity semiconductor film and a conducting film containing at least a low-resistivity semiconductor film without exposing them to an oxidizing atmosphere, a third step in which said high-resistivity semiconductor film and said conducting film are selectively etched so that they are partly left as an island region on said gate electrode, a fourth step for selectively forming a source electrode and a drain electrode both contacting a part of the surface of said island region and spaced apart from each other, a fifth step for selectively removing said conducting film exposed on said island region with said source and drain electrodes serving as at least a part of the mask, a sixth step for depositing a surface passivation film, and a seventh step for selectively removing said surface passivation film and exposing a part of each of said source electrode, drain electrode and gate electrode.