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Proceedings Paper

First-principles simulation of GaN material and devices: an application to GaN APDs
Author(s): Enrico Bellotti; Michele Moresco; Francesco Bertazzi
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Paper Abstract

This work provides a contribution toward the development of a fitting-parameter-free model to describe the high field electron and hole transport in wurtzite GaN. We have developed a novel model for the carrier-phonon interaction in wurtzite GaN based on the rigid pseudoion approach, using the nonlocal empirical pseudopotential method to calculate the electronic structure and the linear response technique within density functional theory to determine the phonon dispersion. This approach makes it possible to eliminate the use of adjustable parameters and to compute the deformation potential interaction parameters both for electron- and hole-phonon scattering rates directly from first-principle. On the same footing the electrons and holes impact ionization rates and the polar carrier-phonon interaction have been computed using the GaN full band structure. Because of the complex GaN band structure, it is necessary to properly account for the multiband transport phenomena that significantly change the carrier dynamics at high energies. Neglecting this effect, would result in a significantly lower impact ionization coefficients and, as a consequence, smaller multiplication gains and higher breakdown voltages in APDs. To evaluate the ability of the new model to predict the performance of realistic devices, we have computed the electrons and holes multiplication gains, noise factors, breakdown voltages and bandwidth of different APD structures fabricated on different crystallographic planes and performed a detailed comparison with the available experimental data. We find that the model correctly predicts, within the experimental errors, the multiplication gains and breakdown voltages of several devices structures.

Paper Details

Date Published: 10 March 2010
PDF: 9 pages
Proc. SPIE 7602, Gallium Nitride Materials and Devices V, 76021B (10 March 2010); doi: 10.1117/12.842088
Show Author Affiliations
Enrico Bellotti, Boston Univ. (United States)
Michele Moresco, Boston Univ. (United States)
Francesco Bertazzi, Boston Univ. (United States)
Politecnico di Torino (Italy)


Published in SPIE Proceedings Vol. 7602:
Gallium Nitride Materials and Devices V
Jen-Inn Chyi; Yasushi Nanishi; Hadis Morkoç; Cole W. Litton; Joachim Piprek; Euijoon Yoon, Editor(s)

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