CH4 Adsorption Probability on GaN(0001) and (000−1) during Metalorganic Vapor Phase Epitaxy and Its Relationship to Carbon Contamination in the Films

Materials

MichaelR. von Spakovsky¹  Akira Kusaba²  Guanchen Li³  Pawel Kempisty⁴  Yoshihiro Kangawa⁵ 

[1] Center for Energy Systems Research, Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061, USA;Department of Aeronautics and Astronautics, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan;Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK;Institute of High Pressure Physics, Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warsaw, Poland;Research Institute for Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816-8580, Japan;

关键词: metalorganic vapor phase epitaxy;    gallium nitride;    density functional theory calculations;    steepest-entropy-ascent quantum thermodynamics;   

DOI  :  10.3390/ma12060972

来源: DOAJ

【 摘 要 】

Suppression of carbon contamination in GaN films grown using metalorganic vapor phase epitaxy (MOVPE) is a crucial issue in its application to high power and high frequency electronic devices. To know how to reduce the C concentration in the films, a sequential analysis based on first principles calculations is performed. Thus, surface reconstruction and the adsorption of the CH₄ produced by the decomposition of the Ga source, Ga(CH₃)₃, and its incorporation into the GaN sub-surface layers are investigated. In this sequential analysis, the dataset of the adsorption probability of CH₄ on reconstructed surfaces is indispensable, as is the energy of the C impurity in the GaN sub-surface layers. The C adsorption probability is obtained based on steepest-entropy-ascent quantum thermodynamics (SEAQT). SEAQT is a thermodynamic ensemble-based, non-phenomenological framework that can predict the behavior of non-equilibrium processes, even those far from equilibrium. This framework is suitable especially when one studies the adsorption behavior of an impurity molecule because the conventional approach, the chemical potential control method, cannot be applied to a quantitative analysis for such a system. The proposed sequential model successfully explains the influence of the growth orientation, GaN(0001) and (000−1), on the incorporation of C into the film. This model can contribute to the suppression of the C contamination in GaN MOVPE.

【 授权许可】

Unknown