Aluminium nitride (AlN) is a widely used semiconductor material in several electronic devices due to its direct wide bandgap of 6.2 eV 2 . The conventional method for depositing epitaxial films of AlN is chemical vapor deposition (CVD) using trimethylaluminium (TMA), Al2(CH3)6 and ammonia, NH3, at temperatures, typically, above 1000 C . This limits the applications for AlN to substrates and underlying film materials that can withstand such temperatures. An alternative low temperature deposition route is atomic layer deposition (ALD), which is a timeresolved form of CVD where the Al and N precursors are pulsed into the deposition chamber sequentially, separated by inert gas pulses. This gas pulsing makes the process solely depend on surface chemical reactions and omits gas phase chemical reactions, which typically need high temperatures. ALD of AlN have previously been reported using TMA with NH3 both via thermal , NH3 plasma7 ,8,9,10 and N2 plasma routes. Plasma processes can lead to crystalline and conformal AlN films at temperatures <300 °C. To obtain a crystalline AlN film via the thermal route, a temperature >375 °C is needed. The TMA molecule is reported to decompose above 330 °C12 by breaking of one of the Al-C bonds, forming dimethyl aluminium (DMA) and a methyl group at temperatures 500 °C. Thermal ALD of AlN typically contain 5-10 at.% C depending on the deposition temperature, making thermal ALD routes not ideal for depositing electronic grade AlN. Plasma ALD is also associated with high levels of carbon impurities as atomic hydrogen, produced in the plasma discharge, can induce a chemistry trapping carbon impurities in the film by abstracting H2 from surface methyl groups. Deposition of crystalline AlN with low levels of carbon is thus dependent on an efficient carbon cleaning surface chemistry.