The application of ammonium sulfide chemical treatments for molecular beam epitaxy regrowth is examined. Reflection high‐energy electron diffraction, transmission electron microscopy, and capacitance‐voltage profiling techniques are used to investigate the regrown interface. A slight enhancement of the electron concentration is seen at the regrown interface due to the incorporation of residual sulfur atoms as donors. The amount of residual sulfur donors is a strong function of the substrate temperature at which regrowth is initiated.