Process Optimization for RF Performance of Ion-Implanted E/D MESFETs

D. Becher, S.C. Shen, D. Caruth, and M. Feng
High Speed Integrated Circuits Group
Department of Electrical and Computer Engineering, University of Illinois

Results are presented from a design of experiments targeted towards extending the use of ion-implanted MESFETs to higher frequencies. The implant schedule is optimized to achieve a shallow, abrupt profile while maintaining high peak carrier concentration. Minimizing the source-drain spacing improves the high frequency performance. The resulting d-mode and e-mode devices both have f t over 120 GHz and f max over 160 GHz, making the device an excellent candidate for low-cost, high-performance wireless and fiber channel applications.