SEMICONDUCTOR DEVICE SUBSTRATE, SEMICONDUCTOR DEVICE, AND METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

摘要

This semiconductor device substrate has: a substrate; a buffer layer, which is provided on the substrate, and is formed of a nitride semiconductor; and a device active layer configured from a nitride semiconductor layer provided on the buffer layer. The semiconductor device substrate is characterized in that: the buffer layer contains carbon and iron; the carbon concentration of the upper surface of the buffer layer is higher than the carbon concentration of the lower surface of the buffer layer; and the iron concentration of the upper surface of the buffer layer is lower than the iron concentration of the lower surface of the buffer layer. Consequently, provided is the semiconductor device substrate wherein a leak current in the lateral direction in high-temperature operation is reduced, while suppressing a leak current in the longitudinal direction.