High uniformity, highly reproducible non-selective wet gate recess etch process for InP HEMTs
Xin Cao, Iain Thayne
Ultrafast Systems Group, Department of Electronics and Electrical Engineering
Keywords: WET ETCH, INP, HEMT
A new non-selective wet etching technique has been developed to etch In0.53Ga0.47As/In0.52Al0.48As structure for the gate recess of InP HEMTs. Both precise etch depth and well-controlled undercut width were achieved. Very smooth etched surface was also demonstrated by this new etching technique. 120nm gate length InP HEMTs were fabricated using this new gate recess process. A maxium transconductance, gm of 660 mS/mm and current cut-off frequency, fT of 250 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.