Precursors with chelating ligands forming N-In bonds have also been used successfully to deposit InN with NH3 plasma. However, a thermal ALD process has not been shown experimentally. This is in contrast to the other group 13-N semiconductors AlN and GaN which both has been grown using thermal NH3 and trimethyl aluminum (TMA, Al(CH3)3) and trimethyl gallium (TMG, Ga(CH3) 3) 13,14 respectively. Since plasma ALD of InN gives films with TMI, and since the plasma discharge is not activated when TMI is exposed to the NHx covered InN surface, it is reasonable to assume that the limitation to a thermal ALD process for InN is found in the interaction between NH3 and the -In(CH3)x covered InN surface. Although it is thermodynamically favorable for NH3 to decompose into N2 and H2 at the temperatures in the ALD processes, the decomposition is limited by very slow kinetics at these temperatures, making NH3 stable during the residence time in ALD. The majority of the NH3 molecules are therefore expected to arrive to the surface intact in thermal ALD, contrasting plasma ALD processes where the plasma decompose the NH3 molecules into more reactive species. Ab initio calculations on NH3 adsorption have been reported earlier on GaN by Krukowski and co-authors. I their work they have shown that upon adsorbing onto a bare GaN surface, NH3 can form a variety of different NHx surface species located at different adsorption sites. By thermodynamic analysis they derived the stability of these species and investigated the prevalence at different partial pressures of NH3 and H2. Using a similar approach, we investigated the stability of different NHx surface species on AlN, GaN and InN. Here we also found that there exists different stable configurations of NHx with similar structures on all three materials. In these studies, NH3 is modeled to adsorb on a bare surface allowing it to easily reach an adsorption site. However, after thermal adsorption of trimethyl metal precursors the adsorption sites would be blocked by methyl groups, kinetically hindering initial adsorption.