SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

摘要

PURPOSE: A semiconductor device and a method for manufacturing the same are provided to obtain high field effect mobility by forming a channel formation region in an oxide semiconductor. CONSTITUTION: A first oxide semiconductor layer(403) includes a gate insulation layer(402), a gate electrode layer(401) and a channel formation region. The first oxide semiconductor layer includes indium, gallium and zinc. A source electrode layer(405a) and a drain electrode layer(405b) are formed on the first oxide semiconductor layer. A second oxide semiconductor layer is formed between the first oxide semiconductor layer and the source electrode layer. A third oxide semiconductor layer is formed between the first oxide semiconductor layer and the drain electrode layer.