Optimum Au/WSi 0.3 μm-gate-length n-HIGFETs for microwave power applications in X band

An investigation of pseudomorphic Ga/sub 0.25/Al/sub 0.75/As/Ga/sub 0.80/In/sub 0.20/As/GaAs heterostructure insulated-gate FETs (HIGFET) far microwave power applications is presented. Devices have been fabricated using Au/WSi self-aligned gate technology with SiO
₂
sidewalls. The fabrication process has been optimized in order to realize 0.3 μm gate-length transistors with reduced short-channel effects and improved rf power performance. dc and rf extracted parameters suggest very attractive capabilities: for N-type HIGFET, a current density of 460 mA/mm and an extrinsic transconductance of 480 mS/mm are obtained. Measurements at 10 GHz using a load-pull power setup have been carried out: 300 mW/mm maximum output power, 14 dB linear gain, and 65% PAE, for low Vds (3 V) value. To our knowledge, these power results are the first reported for 0.3 μm-HIGFFTs.