X-band MMIC switch with 70 dB isolation and 0.5 dB insertion loss

A single-pole, single-throw reflective MMIC switch with 0.5 dB insertion loss and 70 dB isolation over X-band has been demonstrated. A fabrication process that was optimized to achieve the best performance for switch FETs produced this exceptional device. The FET OFF capacitance was reduced by a factor of 1.6 by selectively recessing into the backside of the wafer underneath the FETs to within 1 /spl mu/m of the top surface. The FET ON resistance remained the same. The reduced FET OFF capacitance allowed the use of larger periphery FETs to obtain the improved performance. The Ron-Coff product of this device is 30% lower than previously reported results.<>