Gallium Nitride Doping with Carbon: A Thermodynamic Analysis

Abstract

A thermodynamic model of GaN doping with carbon accompanied by native defect formation is developed, based on ab initio calculations as input data. A correction procedure for defect formation energies is suggested to account for realistic growth conditions and thermodynamic reservoir, providing atomic exchange involved in impurity incorporation and defect generation. Applied to undoped and Si‐doped GaN grown by metal‐organic vapor phase epitaxy (MOVPE), the model demonstrates the amphoteric nature of carbon, leading to simultaneous formation of donor and acceptor states. The role of nitrogen vacancies controlling background electron conductivity in undoped GaN and the carbon distribution between cation and anion sites as a function of growth conditions are also discussed in terms of the model. The relationship between the total carbon concentration in GaN and the density of traps capable of capturing electrons is analyzed, which is important for GaN:C application as a high‐resistance buffer material for electronic devices.