The effect of surface preparation on the production of low interfacial charge regrown interfaces

Many optical and digital device structures could be enhanced by the ability to grow highly perfect interfaces on surfaces which have been chemically processed. Growth surfaces prepared through wet chemical processing typically exhibit a large density of carrier traps at a subsequently grown buried interface. The use of a Br based in-situ vapor etch prior to growth has been developed to substantially improve the electrical behavior of these interfaces. The removal of only ~ 0.02 μm of surface through the vapor etch at 800°C is sufficient to reduce the trap density. Such an in-situ vapor does not significantly reduce the concentration of chemical contaminates at the buried interface implying a change in the electrical behavior of impurities due to the vapor etch. © 1986.