AVS 52nd International Symposium
    Electronic Materials and Processing Monday Sessions
       Session EM+NS-MoM

Paper EM+NS-MoM11
Determining Composition of HPCVD Indium Nitride with Auger Electron Spectroscopy

Monday, October 31, 2005, 11:40 am, Room 310

Session: Novel Approaches in Wide Bandgap Semiconductors
Presenter: R.P. Bhatta, Georgia State University
Authors: R.P. Bhatta, Georgia State University
B.D. Thoms, Georgia State University
V.T. Woods, Georgia State University
M. Alevli, Georgia State University
N. Dietz, Georgia State University
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Indium Nitride (InN), a wurtzite structure III-V semiconductor with a direct bandgap, has potential for use in many optoelectronic applications. In addition, alloys of InN, GaN, and AlN cover a large spectral range from 0.6 eV up to 6 eV which can be utilized in many novel optoelectronic devices. The low growth temperatures usually needed for growth and stability of InN have limited the use of widely varying alloy compositions in the same device. High pressure chemical vapor deposition (HPCVD) allows InN to be grown at temperatures similar to those of GaN and AlN. There has recently been considerable debate regarding the value of the energy bandgap of InN and its relationship to the concentration of oxygen in the film. The optical analysis of InN layers grown under HPCVD shows that the shift of the absorption edge down to 0.63 eV is caused by a series of absorption centers. The appearance of these absorption centers is closely related to the indium and nitrogen point defect chemistry, which can be controlled through the molar flow ratio of the precursors. In this contribution, the compositional analysis of HPCVD grown InN films by Auger Electron Spectroscopy (AES) is presented. The proximity of the nitrogen and indium AES peaks makes determination of nitrogen to indium ratios more difficult. It has been reported that ion sputtering reduces the nitrogen content in InN films. While this study also reports that sputtering reduces the relative peak-to-peak height for dN/dE spectra, a substantial reduction is not observed in the relative integrated intensities for undifferentiated spectra. We conclude that sputtering has a large effect on the lineshape of nitrogen AES peaks but does not substantially reduce the nitrogen concentration. The concentrations of contaminants such as carbon and oxygen were analyzed and correlated with film properties measured by Raman and absorption spectroscopy.