0.15 MU-M T-GATE E-BEAM LITHOGRAPHY USING CROSS-LINKED P(MMA MAA) DEVELOPED IN ORTHO-XYLENE RESULTING IN HIGH-CONTRAST AND HIGH PLASMA STABILITY FOR DRY-ETCHED RECESS GATE PSEUDOMORPHIC MODFETS FOR MMIC PRODUCTION/

Pseudomorphic AlGaAs/InGaAs/GaAs modulation doped FETs (psi-MODFETs) w ith sub quarter micron gate length are used in millimeter-wave amplifi ers. To reduce the noise figure and enhance the cut-off frequency T-ga te technology is required. To enhance device reliability and yield, th e gate recess depth and width must be precisely controlled. Selective reactive ion etching (RIE) of GaAs on thin AlGaAs etch stop layers usi ng Freon-12 as an etch gas satisfies these conditions. The e-beam patt erned T-gate resist profile has to withstand this dry-etched gate rece ss process. [GRAPHICS] Using a novel three layer resist system with cr osslinked P(MMA/MAA) we were able to pre duce 76 GHz amplifiers with a gain of 21 dB, broadband amplifiers 5-80 GHz with 9 dB gain and dynam ic frequency dividers operating in a range of 26-51 GHz based on 0.15 mu m T-gate pseudomorphic MODFETs.