| abstract |
A semiconductor device, comprises: a semiconductor layer, a first gate insulating film, a second gate insulating film and a gate electrode. The semiconductor layer is mainly made of gallium nitride (GaN). The first gate insulating film is formed on the semiconductor layer by atomic layer deposition using ozone as an oxidizing agent and is mainly made of an oxide. The second gate insulating film is formed on the first gate insulating film by atomic layer deposition using oxygen plasma as an oxidizing agent, and is mainly made of an oxide and contains carbon (C) at a lower concentration than that in the first gate insulating film. The gate electrode is formed on the second gate insulating film. |