Novel high uniformity highly reproducible non-selective wet digital gate recess etch process for InP HEMTs

Abstract

A new non-selective wet digital etching technique has been developed to etch In 0.53Ga 0.47As/In 0.52Al 0.48As structure for the gate recess of InP High Electron Mobility Transistors (HEMTs). Both precise etch depth and well-controlled undercut width were achieved. A very smooth etched surface was also demonstrated by this new etching technique. 120 nm gate length InP HEMTs were fabricated using this new gate recess process. A maximum transconductance, g m, of 600 mS/mm and current cut-off frequency, f T, of 175 GHz were achieved. Those devices performances are comparable to the best results we have achieved by using other gate recess technique. Finally, this new recess etching process is highly uniform and reproducible.