GIXRD measurement shows that the films consist of polycrystalline, hexagonal AlN and that the crystallinity of the films increases with the time for the H2 pulse, as seen that the intensity of the (100) plane more than triples when the H2 is added (black line) compared to without a H2 (red line) (Fig. ). The full width at half maximum value (FWHM) for the (100) plane also decreases from 0.657 to 0.503 upon addition of the H2 pulse, indicating a higher degree of crystallinity. This shows that adding a H2 pulse not only decreases the carbon content in the film, but also increases the crystallinity. By using the Debye-Scherrer equation an approximate crystallite size of 17 nm was calculated using the FWHM of the AlN (100) peak for 19.5 H2 exposure. The crystallite size was calculated to approximately 17 nm. Figure To test if the reduction in carbon content was due to a surface chemical reaction between surface methyl groups and the hydrogen gas, N2 and Ar were also tested as purge gas between the TMA and NH3 pulse. The pulse time for H2, N2 and Ar was kept constant at 19.5 s. XPS measurements show that the carbon content in the films is 1±0.4 at.% independent of which gas that is used.