COMPOUND SEMICONDUCTOR DEVICE

摘要

PURPOSE:To reduce a variation in pinch off voltage and to cut an excessive prolongation in the tailing characteristics of ID-VG by forming a layer doped in P type between a semiinsulating substrate and an active layer on the whole surface of a wafer. CONSTITUTION:In a field effect transistor using a compound semiconductor, a semiconductor layer 10 having a conductivity type opposite to that of an active layer is provided between the said semiinsulating substrate crystal 1 and the active layer 3 and electrodes 4, 5 controlling the layer 10 is provided. This can reduce a variation in pinch off voltage.