Patent ID: 9276066
Filing Date: 2016-03-01
CPC Classification: H01L

Claim Text:
1. A semiconductor multi-layer substrate comprising: a substrate; a buffer layer formed on the substrate and made of a nitride semiconductor; an electric-field control layer formed on the buffer layer and made of a nitride semiconductor, the electric-field control layer having conductivity in the substrate's lateral direction; an electric-field relaxation layer formed on the electric-field control layer and made of a nitride semiconductor; and an active layer formed on the electric-field relaxation layer and made of an nitride semiconductor, wherein a resistance in the substrate's lateral direction of the electric-field control layer is equal to or smaller than 10 times a resistance of the electric-field relaxation layer, a ratio of an electric field share between the electric-field relaxation layer and the buffer layer is controlled by a ratio between a thickness of the electric-field relaxation layer and a thickness of the buffer layer, and a ratio of a distance between an upper surface of the electric-field relaxation layer and an upper surface of the electric-field control layer relative to a sum of the thicknesses of the buffer layer, the electric-field control layer, and the electric-field relaxation layer is within a range of 0.3 to 0.8.