Fabrication of 0.1-μm planar-doped pseudomorphic HEMT´s using a PECVD silicon nitride assisted process

A Plasma Enhanced Chemical Vapour Deposited (PECVD) silicon nitride assisted process has been successfully used to fabricate 0.1-μm gate-length planar-doped AlGaAs/InGaAs/GaAs pseudomorphic High Electron Mobility Transistors (HEMT´s). Excellent d.c. and microwave performances are achieved by these devices, demonstrating the suitability of the process for fabricating ultrashort gate length devices. Moreover, it is shown that the process offers the possibility of decreasing the resistance of ultrashort gate fingers by forming mechanically stable T-gates.