With the high-quality Si₃N₄ dielectric by low-pressure chemical vapor deposition (LPCVD) and damage free, self-terminating passivation layer etching at the gate area, the MIS-HEMTs on 150 mm Si substrate demonstrate excellent output performance and good uniformity. The degradation of dynamic on-resistance is only about 42% at a quiescent drain bias of 600 V.