Manufacturability of dummy-gate self-aligned LDD GaAs MESFETs for high volume production

A manufacturable self-aligned LDD GaAs MESFET process called SRD has been developed. In this process, we controlled the fabrication conditions from lot to lot. Excellent control of the device characteristics not only across the wafer but also from wafer to wafer is obtained. The controllability of Vth is within /spl plusmn/50 mV. The standard deviation of Vth across the 3-in wafer is less than 30 mV for 0.5 /spl mu/m devices. In addition, other parameters such as g/sub m/, g/sub d/ are also well controlled within /spl plusmn/7% (Max-Min).