Patent ID: 7352017

Claim:
A nitride semiconductor device, comprising a III-V group nitride semiconductor layer formed of III group elements including at least one element from the group consisting of gallium, aluminum, boron and indium, and V group elements including at least nitrogen from the group consisting of nitrogen, phosphorous and arsenic, comprising a first nitride semiconductor layer made of said III-V group nitride semiconductor layer deposited on a substrate, a second nitride semiconductor comprising said III-V group nitride semiconductor layer deposited on the first nitride semiconductor layer and not including aluminum, and a control electrode making Schottky contact with said first nitride semiconductor layer being exposed through a portion of the second nitride semiconductor layer that has been removed, wherein said second nitride semiconductor layer is made of crystallinity with minute grains, wherein the control electrode making Schottky contact with said first nitride semiconductor layer being exposed through a portion of said second nitride semiconductor layer, where the portion is a region where the control electrode is planned to be formed, that has been removed, and a source electrode and a drain electrode which make ohmic contact with said first nitride semiconductor layer in a manner where a current that flows through a channel that is made of said first nitride semiconductor layer or a channel that is formed between a third nitride semiconductor layer and said first nitride semiconductor layer is controlled by a voltage that is applied to said control electrode.