Patent ID: 8089096

Claim:
A field effect transistor, comprising: a first semiconductor layer which is made of a first hexagonal crystal with 6 mm symmetry and has a main surface including a C-axis of the first hexagonal crystal; a second semiconductor layer which is formed directly on the main surface of said first semiconductor layer and is made of a second hexagonal crystal with 6 mm symmetry having a band gap different from a band gap of the first hexagonal crystal; a gate electrode; a source electrode; and a drain electrode, wherein said gate electrode, said source electrode and said drain electrode are formed on said second semiconductor layer, a film thickness of said first semiconductor layer is 1.5 μM or less, said second semiconductor layer has an n-type conductivity, and a longitudinal direction of said gate electrode is orthogonal to the C-axis and to an alignment direction of said source electrode and said drain electrode.