Kinetics of AsCl3 chemical beam etching of GaAs(001), (111)A and (111)B surfaces

In situ AsCl3 etching of (111)A, (111)B and (001) GaAs layers has been stud ied as a function of substrate temperature in the range of 450-600 degrees C. The (111)A and (001) show qualitatively the same etching behavior. For b oth substrates, the etching rate is thermally activated below 500 degrees C and stays constant for higher temperature. In contrast, the (111)B plane i s not etched for temperature lower than 540 degrees C. The difference in et ching behavior between (111)A and (111)B is tentatively explained from the relative arsenic surface concentration stability of the (111)A and (111)B s urface temperature. The strong temperature dependence of etching rate betwe en (111)A and (111)B plane explains qualitatively the different shape the e dges observed when GaAs(001) selective area etching is performed through Si O2 mask openings. (C) 1999 Published by Elsevier Science B.V. All rights re served.