Self-aligned shallow junction MJFET (metal junction FET) for higher turn-on and breakdown voltages

Simple self-aligned p/sup ++/-gate formation technology for a junction field-effect transistor (JFET) using elemental shallow Zn diffusion from patterned Au/Zn gate metal is reported. This diffusion technology makes it possible to control a very shallow p/sup ++/-layer less than 50 nm. The metal junction FET (MJFET) shows about 0.3 V higher gate turn-on voltage in forward bias and much larger reverse breakdown voltage than the conventional Al-gate MESFET with similar transconductances, typically 200 mS/mm for 1.5- mu m gate length quasi-enhancement, and 90 mS/mm for 4- mu m gate length deep depletion devices.<>