The behavior of unintentional impurities in Ga0.47 In0.53As grown by MBE

A number of factors contribute to the high n-type background carrier concentration (high 1015 to low 1016 cm-3) measured in MBE Ga0.47In0.53As lattice-matched to InP. The results of this study indicate that the outdiffusion of impurities from InP substrates into GalnAs epitaxial layers can account for as much as two-thirds of the background carrier concentration and can reduce mobilities by as much as 40%. These impurities and/or defects can be gettered at the surfaces of the InP by heat treatment and then removed by polishing. The GalnAs epitaxial layers grown on the heat-treated substrates have significantly improved electrical properties. Hall and SIMS measurements indicate that both donors and acceptors outdiffuse into the epitaxial layers during growth resulting in heavily compensated layers with reduced mobilities. The dominant donor species was identified by SIMS as Si, and the dominant acceptors as Fe, Cr and Mn. © 1985 AIME.

Duke Scholars

Author April S. Brown Electrical and Computer Engineering