Technical aspects of InGaAs MOMBE -- shutter action, system drift, and material quality

Abstract

Lattice matched InxGa1 - x As films were deposited on InP substrates using metalorganic molecular beam epitaxy (MOMBE) with trimethylindium (TMIn), triethylgallium (TEGa) and a solid arsenic source. The effect of growth temperature and molecular beam composition on growth rate and crystal composition was investigated. A long term drift of the molecular beam composition and an increasing difference between temperature readings of the thermocouple and the pyrometer were observed. The corrected data show a linear dependence of crystal composition on molecular beam composition. Shutter action on TMIn and TEGa was investigated. The results show the adverse effect of solely using the shutters to control the metalorganic molecular beam, leading to inferior material quality and rough surface morphology. Material grown in the optimized process consistently showed electron mobilities of [mu]300 [approximate] 9000 cm2/V[middle dot]s and [mu]77 [approximate] 35,000 cm2/[middle dot]s at 1.2 x 1015 cm-3 n-type background concentration.