High-mobility inverted selectively doped heterojunctions

We have used reflection high-energy electron diffraction (RHEED) to study the surface recovery of AlGaAs under different conditions. A modified process for growth interruptions was then introduced, where a GaAs monolayer was grown at each growth stop, and the arsenic flux was turned off during the low-temperature phase of growth interruptions. Selectively doped inverted heterojunctions were grown using the modified growth interruptions together with low-growth temperature (to avoid Si and impurity segregation). This combined process gave reproducible electron mobilities as high as 460 000 cm2/V s with sheet carrier concentration of 2×1011 cm−2 at 4.2 K.