Described herein are compositions, silicon nitride films and methods for forming silicon nitride films using at least on cyclodisilazane precursor. In one aspect, there is provided a method of forming a silicon nitride film comprising the steps of: providing a substrate in a reactor; introducing into the reactor an at least one cyclodisilazane comprising a hydrocarbon leaving group and two Si—H groups wherein the at least one cyclodisilazane 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 nitrogen and an inert gas 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.