Survival of atomic monolayer steps during oxide desorption on GaAs (100)

Abstract

Significant surface pitting and a degraded surface roughness are almost always observed on GaAs (100) surface after conventional thermal oxide desorption. Here we report on the use of a Ga-triggered low temperature oxide desorption method that can be used to preserve the atomic monolayer (ML) steps. By providing an external supply of atomic Ga at a relatively low substrate temperature of ∼450°C without an As4 overpressure, this technique resulted in an atomically smooth GaAs ML steps with a root mean square roughness of 0.25nm, nearly identical to as-grown GaAs surface (0.2nm). The demonstrated results show the potential for applications in optoelectronics such as regrowth and patterned substrate growth.