A High-Efficiency Power FET Fabricated using Co-Implantation and a Self-Aligned Gate

We discuss the design, fabrication and measured RF performance of fully planar, refractory, self-aligned gate (SAG) power FETs. The FET active channels are formed by direct ion-implantation into substrate. The performance and uniformity of these FETs are significantly improved by the use of a co-implant of n- and p-type dopants. The channel thickness and sheet charge are empirically adjusted for peak RF performance. The effects of channel characteristics on RF performance are demonstrated using a C-Band power MMIC as a test vehicle.