Effect of inert gas additive species on Cl2 high density plasma etching of compound semiconductors Part II.: InP, InSb, InGaP and InGaAs

The effects of the additive noble gases He, Ar and Xe on chlorine-based inductively coupled plasma etching of InP, InSb, InGaP and InGaAs were studied as a function of source power, chuck power and discharge composition. The etch rates of all materials with Cl-2/He and Cl-2/Xe are greater than with Cl-2/Ar. Etch rates in excess of 4.8 mu m/min for InP and InSb with Cl-2/He or Cl-2/Xe, 0.9 mu m/min for InGaP with Cl-2/Xe, and 3.8 mu m/min for InGaAs with Cl-2/Xe were obtained at 750 W ICP power, 250 W rf power, similar to 15% Cl-2 and 5 mTorr. All three plasma chemistries produced smooth morphologies for the etched InGaP surfaces, while the etched surface of InP showed rough morphology under all conditions. (C) 1999 Elsevier Science B.V. All rights reserved.