Nitrogen Plasma Etching and Surface Passivation of GaAs via Plasma-Enhanced Atomic Layer Deposition

Abstract

We investigated the suitability of aluminum nitride (AlN) for surface passivation and protection of gallium arsenide (GaAs), using a low-temperature passivation method. By varying the plasma power (100, 200 W) during etching, we found that 200 W produced better passivation. Using X-ray photoelectron spectroscopy, we quantitatively demonstrate that etching the GaAs at 200 W almost removed the GaAs oxide layer. To further study the surface passivation of GaAs, we deposited an AlN film by plasma-enhanced atomic layer deposition using trimethylaluminum and ammonia precursors at 250 °C. AlN passivation did not effectively smooth the GaAs surface, but did increase its photoluminescence intensity. This study shows that AlN coating by plasma-enhanced atomic layer deposition is a promising low-temperature method for GaAs surface passivation.