New vertical silicon microwave power transistor structure and package with inherent thermal self protection

A novel vertical silicon high voltage microwave power transistor is reported with high degree of robustness and inherent thermal self protection. The HVVFET device uses a deep dielectric platform with uniform channel doping that approaches near ideal breakdown voltages (> 110 Volts) for suitable epitaxial thickness and doping levels resulting in high power density. An integrated shield enables significant reduction in the feedback capacitance resulting in devices with f_T > 6 GHz and gain in excess of 15 dB, with VSWR of 20:1. Flip-chip gold bumps are used to achieve short thermal transfer path to the flange and achieve inherent thermal self protection.