Effects of doping type and concentration on precipitation of nanometer arsenic clusters in low-temperature-grown GaAs

Abstract

In this study, the effects of doping type and concentration on arsenic precipitation in low-temperature-grown GaAs upon postgrowth annealing at 600, 700. and 800 degrees C were investigated. Three undoped/Si-doped/undoped (i-n-i) regions and three undoped/Be-doped/ undoped (i-p-i) regions were grown by low-temperature Molecular beam epitaxy, The results show that arsenic precipitation is dependent on doping type and doping concentration. Arsenic depletion was observed in all Be-doped layers for all annealing temperatures. However, a "dual" arsenic precipitation behavior was observed in Si-doped layers: As accumulates in [Si]=2 X 10(18) cm(-3) doped layers, while it depletes in [Si]=2 X 10(16) and 2 X 10(17) cm(-3) doped layers, We attribute this "dual" As precipitation phenomenon in Si-doped layers to the different depletion depths. (c) 2005 American Vacuum Society.