Patent ID: 9029873
Filing Date: 2015-05-12
Classification: H01L

Abstract:
1. A semiconductor device comprising: a silicon carbide (SIC) substrate; an aluminum nitride (AlN) layer provided on the SiC substrate and having an island-shaped pattern consisting of plural islands; a channel layer provided on the AlN layer and comprising a nitride semiconductor; an electron supplying layer provided on the channel layer and having a band gap larger than that of the channel layer; and a gate electrode, a source electrode and a drain electrode provided on the electron supply layer, wherein the AlN layer has an area-averaged circularity Y/X of greater than 0.2, in which Y is a sum of values obtained by multiplying circularities of the plural islands by areas of the plural islands respectively, and X is a sum of the areas of the plural islands, the circularity being calculated by a formula of (4π×area)/(length of periphery)