NOVEL HIGH-YIELD TRILAYER RESIST PROCESS FOR 0.1 MU-M T-GATE FABRICATION

By utilizing a novel ZEP/PMGI/ZEP trilayer resist process, GaInAs/AlIn As T-gate modulation-doped field effect transistors on InP with 0.1 mu m gate lengths have been demonstrated. The trilayer resist requires o nly a single exposure. An overhang structure for liftoff, with a 0.1 m u m footprint, is created by a sequence of infinitely selective develo pments for each layer. Linewidths as narrow as 65 nm have been obtaine d. Devices with a maximum current of 860 mA/mm, extrinsic transconduct ances of 658 mS/mm, and a current-gain-cutoff frequency f(t) of as hig h as 203 GHz have been fabricated. Yields as high as 96% and a thresho ld voltage uniformity of 34 mV (1 sigma) have been achieved on a 2 in, wafer. (C) 1995 American Vacuum Society.