AVS 53rd International Symposium
    Electronic Materials and Processing Wednesday Sessions
       Session EM-WeM

Paper EM-WeM13
Surface Electron Accumulation in Indium Nitride Layers Grown by High Pressure Chemical Vapor Deposition

Wednesday, November 15, 2006, 12:00 pm, Room 2003

Session: New Directions in Compound Semiconductors
Presenter: B.D. Thoms, Georgia State University
Authors: R.P. Bhatta, Georgia State University
B.D. Thoms, Georgia State University
A. Weerasekera, Georgia State University
A.G.U. Perera, Georgia State University
M. Alevli, Georgia State University
N. Dietz, Georgia State University
Correspondent: Click to Email
High resolution electron energy loss spectroscopy (HREELS) has been used to characterize vibrational and electronic properties of indium nitride layers grown by high pressure chemical vapor deposition. HREEL spectra acquired using incident electron energy of 7 eV from atomic hydrogen cleaned InN layers showed loss peaks due to the Fuchs-Kliewer surface phonon at 560 cm@super -1@ and bending and stretching vibrations of surface N-H at 870 and 3260 cm@super -1@, respectively, indicating N-polarity of the InN layer. HREEL spectra acquired using incident electron energies from 7 to 35 eV exhibited a peak due to a conduction band plasmon excitation. The peak position shifted to lower energy as the incident electron energy was increased indicating a higher plasma frequency and a larger carrier concentration at the surface than in the bulk, which in turn implies a surface electron accumulation layer. The peak energy of the plasmon varied from 3100 to 4200 cm@super -1@ from a set of locations across the surface of the film. Room temperature infrared reflection measurements in the range of 200-8000 cm@super -1@ were acquired at comparable locations across the film and fit to using a three phase thin film reflection model. Plasma frequencies determined from the model fits are in good agreement with plasmon peak energies observed in HREELS at higher incident electron energies. Carrier concentrations determined from the infrared data vary across the film from 8.2x10@super 19@ to 1.4x10@super 20@ cm@super -3@ and carrier mobilities vary from 100 to 210 cm@super 2@/Vs.