SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a semiconductor device with sufficiently low off-state current.SOLUTION: An oxide semiconductor material in which holes have a larger effective mass than electrons is used. A transistor includes on a substrate: a gate electrode layer; a gate insulating layer; an oxide semiconductor layer having heavy holes whose effective mass is 5 or more times, preferably 10 or more times, further preferably 20 or more times the effective mass of electrons; a source electrode layer in contact with the oxide semiconductor layer; and a drain electrode layer in contact with the oxide semiconductor layer.