SEMICONDUCTOR DEVICE MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a thin film transistor using an oxide semiconductor layer, which reduces contact resistance between the oxide semiconductor layer and a source electrode layer or between the oxide semiconductor layer and a drain electrode layer to achieve stable electrical characteristics; and provide a manufacturing method of the thin film transistor.SOLUTION: A manufacturing method of a thin film transistor using an oxide semiconductor layer comprises the steps of: forming on the oxide semiconductor layer, a buffer layer having electrical conductivity higher than that of the oxide semiconductor layer; forming a source electrode layer and a drain electrode layer on the buffer layer; and forming a thin film transistor so as to cause the oxide semiconductor layer and the source electrode layer or the oxide semiconductor layer and the drain electrode layer to be electrically connected via the buffer layer. In the step of forming the buffer layer, the buffer layer having the electrical conductivity higher than that of the oxide semiconductor layer is formed by performing reverse sputtering and heat treatment under a nitrogen atmosphere on the buffer layer.