The ability to deposit thin layers of various types of materials, with great precision, is at the centre of chip production. The complexity of the deposition varies at different steps of the production process. Materials need to be deposited onto large planar surfaces, such as over a full wafer, 300 mm in diameter, or into narrow holes with sub-micrometre diameter and depth to width ratios of >50. Different materials also set challenges during their deposition. For example, highly crystalline compound semiconductors, like Al1-xGaxN, require precise control of the elemental composition, doping concentration, and crystallinity, whilst amorphous dielectric oxides are usually less complicated to deposit.