Dopant patterning of MBE GaAs during growth by very low energy focussed tin ion beam deposition

Abstract

For the first time a focussed ion beam has been used to successfully dope MBE GaAs during growth. GaAs with a mobility of 73 000 cm 2 V −1 s −1 at a carrier concentration of 1 × 10 14 cm −3 has been attained which is the highest mobility MBE GaAs achieved by the technique of ionised beam doping. The use of a tin focussed ion beam as an MBE dopant source has also allowed the three-dimensional patterning of the dopant concentration in GaAs, for the first time. The focussed ion beam apparatus did not interfere with or affect the conventional MBE growth of GaAs and AlGaAs in the chamber.