Nonselective vertical etching of GaAs and AlGaAs/GaAs in high pressure capacitively coupled BCl3/N2 plasmas

We studied nonselective, vertical dry etching of GaAs and AlGaAs/GaAs structure in high pressure capacitively coupled BCl3/N-2 plasmas. The operating pressure was fixed at 150 m Torr. We found that there was an optimized process condition for nonselective and vertical etching of GaAs and AlGaAs/GaAs at the relatively high pressure. It was noted that there was a range of % N-2 (i.e. 20-40%) where nonselective etching of GaAs over AlGaAs could be achieved in the BCl3/N-2 mixed plasma. We also found that dry etching of GaAs and AlGaAs/GaAs structure provided quite vertical and smooth surface when % N-2 Was in the range of 0-20% in the BCl3/N-2 plasma. The maximum etch rates for GaAs (0.41 mu m/min) and AlGaAs/GaAs structure (0.42 mu m/min) were obtained with 20-30% N-2 composition in the plasma. (C) 2009 Elsevier B.V. All rights reserved.