Patent ID: 8921950

Claim:
A semiconductor device comprising: a gate electrode formed on a nitride semiconductor layer, and a source electrode and a drain electrode provided on the nitride semiconductor layer so that the gate electrode is interposed between the source electrode and the drain electrode; a first silicon nitride film that covers the gate electrode and is formed on or above the nitride semiconductor layer between the gate electrode and the source electrode and between the gate electrode and the drain electrode; and a second silicon nitride film that is formed on the first silicon nitride film, wherein a whole stacked layer structure of the first and second silicon nitride films has a tensile stress to the substrate, and a grain density of the first silicon nitride film is denser than that of the second silicon nitride film, wherein the first silicon nitride film has compressive stress of 300 Mpa or more of 1 Gpa or less under a room temperature to the substrate, and wherein the second silicon nitride film has tensile stress of 50 Mpa or more of 1 Gpa or less under a room temperature to the substrate.