Method for manufacturing semiconductor device and semiconductor device

摘要

An object is to provide a semiconductor device in which defects are reduced and miniaturization is achieved while favorable characteristics are maintained. A semiconductor layer is formed; a first conductive layer is formed over the semiconductor layer; the first conductive layer is etched with use of a first resist mask to form a second conductive layer having a recessed portion; the first resist mask is reduced in size to form a second resist mask; the second conductive layer is etched with use of the second resist mask to form source and drain electrodes each having a projecting portion with a tapered shape at the peripheries; a gate insulating layer is formed over the source and drain electrodes to be in contact with part of the semiconductor layer; and a gate electrode is formed in a portion over the gate insulating layer and overlapping with the semiconductor layer.

主权项

1. A semiconductor device comprising:
a semiconductor layer including a channel formation region; a source electrode and a drain electrode formed of a single layer and partly in contact with the semiconductor layer; a gate insulating layer over the source electrode and the drain electrode and in contact with the channel formation region; and a gate electrode overlapping with the channel formation region with the gate insulating layer positioned therebetween, wherein the source electrode and the drain electrode each has a projecting portion, wherein the projecting portion comprises a first surface and a second surface and overlaps with the semiconductor layer, wherein the first surface is a side surface of the projecting portion with a tapered shape, and an angle formed by the first surface and the second surface is more than 90° and less than 180°, wherein a thickness between the second surface and a top surface of the semiconductor layer is thinner than a portion of the source electrode and the drain electrode other than the projecting portion, and wherein the portion is overlapped with the semiconductor layer.