Transport and Chemical Mechanisms in GaN Hydride Vapor Phase Epitaxy
- PDF / 176,102 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 66 Downloads / 210 Views
L3.40.1
Transport and Chemical Mechanisms in GaN Hydride Vapor Phase Epitaxy Sergey Yu. Karpov 1, Alexander S. Segal 1, Darya V. Zimina 1, Sergey A. Smirnov 1, Alexander P. Sid’ko 1, Alexey V. Kondratyev 1, Yuri N. Makarov 2, Denis Martin 3, Volker Wagner 3, and Marc Ilegems 3 1 Soft-Impact Ltd, P.O.Box 33, 27 Engels av., 194156 St. Petersburg, Russia 2 STR Inc, P.O.Box 70604, Richmond, VA 23255, USA 3 Institute for Quantum Electronics and Photonics, Swiss Federal Institute of Technology, CH-1015 Lausanne, Switzerland ABSTRACT On the basis of both experimental and theoretical studies, a simple quasi-thermodynamic model of surface kinetics is suggested for Hydride Vapor Phase Epitaxy (HVPE) of GaN, working in a wide range of growth conditions. Coupled with detailed 3D modeling of species transport in a horizontal reactor, the model provides quantitative predictions for the GaN growth rate as a function of process parameters. Significance of transport effects on growth rate uniformity is demonstrated. INTRODUCTION The development and production of advanced group-III nitride opto- and microelectronic devices, UV light emitting diodes (LEDs) for white solid-state lightning, high-brightness LEDs, laser diodes, high-power field-effect transistors, etc., strongly require a reduced dislocation density in the epitaxial heterostructures. Due to the lack of commercially available GaN and AlN homoepitaxial substrates, alternative approaches based on the growth of these quasi-bulk wafers by HVPE have been widely employed [1]. Much progress has been recently made in fabrication of the quasi-bulk wafers by using the epitaxial lateral overgrowth technique [2-6]. However, despite this progress, the basic mechanisms underlying GaN HVPE are still obscure. In [7], a first kinetic model of surface chemistry was suggested, giving a qualitative interpretation of the effects of carrier gas (hydrogen versus hellium) and temperature on the GaN growth rate. A thermodynamic analysis of GaN HVPE neglecting N2 production due to surface reactions was performed in [8] in order to provide an equilibrium vapor composition at the growth surface and to estimate the thermodynamic driving force for growth. An elaborated kinetic model of heterogeneous processes was suggested by Cadoret et al. (see [9] and references therein) where two distinct growth mechanisms were presented to explain the data of Ref.[7]. The quasithermodynamic approach to surface chemistry combined with 3D simulations of GaN HVPE in a reactor of realistic geometry has revealed the essential effects of gas dynamics and species transport on the growth rate and V/III ratio distribution across the wafer [10]. However, the lack of systematic data at that time did not allow developing of a quantitative HVPE model workable in a wide range of growth conditions. This paper reports on a coupled experimental and theoretical study of GaN HVPE in a horizontal tube reactor aimed at further understanding the basic growth mechanisms. We suggest here a simple quasi-thermodynamic model of surface chem
Data Loading...
