GaAs Heterostructure FET Frequency Dividers Fabricated with a High-Yield 0.5micrometer Direct-Write Trilevel-Gate-Resist.

Frequency dividers and FET test structures have been fabricated on selectively doped n sup + -AlGaAs/GaAs heterostructure FETs (HFETs) with 0.5micrometer gate length electron-beam direct- writing on a novel trilevel resist, EBR- 9/Ge/PMGI. A divide- by-two master/slave frequency divider fabricated with direct- coupled FET logic gates operated up to 9.3 GHz. The input frequency range of a divide-by-two transmission- gate frequency divider was from 3.2 to 12.2 GHz, with a supply voltage of 1.2 V at room temperature. The average propagation delay (fan-in and fan-out =1 ) was 18.2 ps/gate, with a power dissipation of 3.9 mW/stage. With a 3.5 micrometer source-drain spacing, a peak transconductance of 360 mS/mm was measured. The functional yield of both discrete devices and circuits was 92% across 2-inch diameter wafers.