DETERMINATION OF THE STRUCTURE OF GAAS(100)-S WITH CHEMICAL-STATE-SPECIFIC PHOTOELECTRON DIFFRACTION

The chemical passivation of a semiconductor surface is an important step in electronic device manufacturing. This paper describes the application of chemical-state-specific photoelectron diffraction to solve the surface structure of sulfur-passivated GaAs(100). The results show that the GaAs(100)-S surface is terminated with ordered Ga-S-Ga bridge bonds in the [011] azimuth, and on top of this is a disordered arsenic sulfide overlayer. Complex surface structure such as GaAs(100)-S would not be resolved with conventional techniques such as low-energy electron diffraction, x-ray-absorption near-edge structure, surface-extended x-ray-absorption fine-structure, or vibrational spectroscopies.