AVS 53rd International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP14
Surface Characterization of Indium Nitride Layers Grown by High Pressure Chemical Vapor Deposition

Tuesday, November 14, 2006, 6:00 pm, Room 3rd Floor Lobby

Session: Surface Science Poster Session
Presenter: R.P. Bhatta, Georgia State University
Authors: R.P. Bhatta, Georgia State University
B.D. Thoms, Georgia State University
M. Alveli, Georgia State University
N. Dietz, Georgia State University
Correspondent: Click to Email
The growth of InN is difficult due to its low dissociation temperature and the high vapor pressure of nitrogen. High pressure chemical vapor deposition (HPCVD) was developed to overcome these challenges in InN growth. InN layers grown by HPCVD have been studied using several surface sensitive techniques. The InN surface was prepared by a combination of sputtering and atomic hydrogen cleaning (AHC). Auger electron spectroscopy and high resolution electron energy loss spectroscopy (HREELS) showed that AHC alone removes most surface contaminants but that some carbon remains. Argon ion sputtering was used to remove the residual carbon. Following sputter cleaning, AHC at 600 K restores surface order as demonstrated by 1x1 hexagonal low energy electron diffraction pattern. HREEL spectra of the atomic hydrogen cleaned layer show a Fuch-Kliewer surface phonon at 560 cm@super -1@ and adsorbate loss peaks at 3260 and 870 cm@super -1@ assigned to N-H stretching and bending vibrations, respectively. These assignments are confirmed by isotopic shifts using deuterium. No surface In-H vibrations are observed indicating the surface is terminated by N-H species and that the InN layer is N-polar. HREEL spectra also showed loss features due to conduction band plasmon excitations. The plasmon excitation shifted towards higher energy as the incident electron energy was decreased implying a higher plasma frequency at the surface than in the bulk, which in turn implies a surface electron accumulation layer. Electron energy loss spectroscopy in the energy range for electronic excitations was used to investigate the surface electronic structure.