Method of making self-aligned IGFET

摘要

The IGFET is formed on a GaAs wafer which is coated with a layer of Si3N4 and a SiO2 layer. The SiO2 is etched away in transistor areas, and ion implanting provides channel doping. A gate of refractory metal such as Mo is deposited and delineated. The gate and the SiO2 act as masks for ion implantation of the source and drain. The refractory metal gate allows subsequent annealing at high temperatures to activate the ion implanted species.