Adsorption of sodium dodecyl sulfate on cleaning of an N-polar GaN surface in an alkaline solution

Abstract

The present study investigated the removal of contaminated particles from a polished N-polar GaN surface using an alkaline cleaning solution along with sodium dodecyl sulfate (SDS) surfactant. The zeta potential, etch rate, and particle removal efficiency (PRE) of N-polar GaN surfaces were reported. A lower etch rate and smoother N-polar GaN surface were obtained when the surface is treated with a diluted NH4OH solution. However, the etch rate and PRE of the N-polar GaN surface increased as a function of the pH of the NH4OH solution. The PRE of the N-polar GaN surface reached to 96% at pH 10 with a high surface roughness of 0.5nm. SDS was added to the ammonia solutions to control the surface roughness. The N-polar GaN surface reached 100% PRE and surface roughness shown less than 0.4nm when cleaned in a diluted NH4OH solution with 5mM SDS surfactant in a megasonic bath.