Ternary phase diagrams were constructed to investigate the effect on the surface termination at various ratios of N2 and NH3 in the gas as well as the ratio of gas molecules to the number of surface sites. The phase diagrams were constructed by minimizing of the Gibbs energy at a set temperatures and pressures and by varying the initial amount of NH3, N2 and number of surface sites, keeping the total amount constant. Since CVD and ALD usually utilizes a flowing gas The ternary phase diagram for GaN shows many similarities to that of AlN, in the low temperature and pressure case, Figure . The main difference is the absence of phases containing N2 surface dimers. At high temperature and pressure, the surface becomes covered by a mix of H(tp) and bare sites terminations at all compositions under the condition that there is enough hydrogen present in the system. InN also show similarities with AlN and GaN in the low temperature limit, Figure . Most of the compositions yields a large NH2(tp) phase for many and the main difference is the absence of H(tp) containing phases as the amount of NH3 is lowered, since this termination is much less preferred on InN compared to on the other surfaces. At high temperatures the surface becomes bare, with no other phases for any initial compositions.