Thermodynamic analysis of Si doping in GaN

Equilibrium calculations of Si-doping in GaN are investigated using the Gemini code. The method of the calculation is based on the minimisation of the Gibbs free energy. Experimental growth conditions are used for the calculation. The variables are the amount of the dopant and the temperature. The results show the formation of a solid Si3N4 compound with a certain quantity of the input SiH4, that is the silicon precursor in our MOVPE system. Si3N4 formation can explain the limitation of Si incorporation and the surface roughening as revealed by MOVPE Si doped layers.