METHOD OF MAKING A FIELD EFFECT TRANSISTOR

摘要

A method for the fabrication of a gallium arsenide (GaAs) metal-semiconductor field effect transistor (MESFET) is described. The method requires the step of providing a semi-insulating GaAs substrate having thereon a layer of n doped GaAs and another layer of n+ doped Ga1-xAlxAs, the latter being used as a diffusion source for n dopants in selectively doping the n GaAs layer underneath. The fabrication method further includes the step of employing highly directional reactive ion etching on silicon nitride to build insulating side walls thereby to effect the self-alignment of the gate of the MESFET with respect to its source and drain. GaAs MESFET fabricated using this method has its source and drain in close proximity having its gate therebetween. Utilizing the disclosed method, conventional photolithographic techniques can be employed to produce submicron self-aligned GaAs MESFETs.