A novel high-performance WSi-gate self-aligned N-AlGaAs/InGaAs/N-AlGaAs pseudomorphic double heterojunction MODFET by ion implantation

A novel high performance WSi-gate self-aligned N-AlGaAs/InGaAs/N-AlGaAs pseudomorphic double heterojunction MODFET was fabricated by ion implantation into the epitaxial layers. To obtain high activation for the Si implanted epitaxial layers, we have optimized the layer structure, especially AlGaAs thickness, and annealing conditions using a graphite heater. The 0.8 /spl mu/m-gate DH-MODFET exhibited a K-value of 400 mS/Vmm, gm/sub MAX/ of 450 mS/mm and I/sub MAX/ of 300 mA/mm with Vth of -0.05 V. The standard deviation of Vth was 18.1 mV across a 3 inch wafer. Operated with drain bias of 3.0 V, the DH-MODFET demonstrated 28% power added efficiency (PAE) with -56.4 dBc adjacent channel leakage power ratio (ACPR) at P/sub out/=21.5 dBm and 600 kHz off center frequency from 1.9 GHz.