Described herein are methods for forming a Group 13 metal or metalloid nitride film. In one aspect, there is provided a method of forming an aluminum nitride film comprising the steps of: providing a substrate in a reactor; introducing into the reactor an at least one aluminum precursor which reacts on at least a portion of the surface of the substrate to provide a chemisorbed layer; purging the reactor with a purge gas; introducing a plasma comprising non-hydrogen containing nitrogen plasma into the reactor to react with at least a portion of the chemisorbed layer and provide at least one reactive site wherein the plasma is generated at a power density ranging from about 0.01 to about 1.5 W/cm2; and optionally purge the reactor with an inert gas; and wherein the steps are repeated until a desired thickness of the aluminum nitride film is obtained.