A kinetic model for metalorganic chemical vapor deposition from trimethylgallium and arsine

A kinetic model based on the collision theory of chemical reactions is prop osed for gallium arsenide (GaAs) metalorganic chemical vapor deposition fro m trimethylgallium and arsine. A simplified reaction mechanism is incorpora ted into the model, which includes four heterogeneous deposition reactions: Ga-containing and As-containing species with Ga and As sites, as well as c arbon incorporation reactions. An equation for the overall growth rate of t he four deposition reactions is derived, which is simplified under the Ga-r ich or As-rich growth condition. A discussion about antisite defects leads to the conclusion that As-rich growth produces stoichiometric GaAs. The rel ation between temperature and arsine/trimethylgallium ratio for As-rich gro wth is defined. The concept of competitive adsorption is introduced to unde rstand doping and ternary deposition. Carrier concentration for n-type, p-t ype, and amphoteric doping as a function of deposition conditions is derive d. Conversion from p type to n type with arsine/trimethylgallium ratio due to residual carbon is, for the first time, quantitatively explained within the framework of doping. Film composition as a function of deposition condi tions in ternary deposition of aluminum-gallium arsenide (Al1-xGaxAs) and g allium arsenide-phosphide (GaAs1-yPy) is also derived. The distributions of Al and P between gas phase and solid film follow the same physics rule but differ in the nature of impinging species. The quantitative agreement betw een the model and a wide range of experiments demonstrates the value of thi s model. (C) 2000 American Institute of Physics. [S0021-8979(00)00407-2].