Methods for forming a integrated gate dielectric layer on a substrate are provided. In one embodiment, the method includes forming a silicon oxide layer on a substrate, plasma treating the silicon oxide layer, depositing a silicon nitride layer on the silicon oxide layer by an ALD process, and thermal annealing the substrate. In another embodiment, the method includes precleaning a substrate, forming a silicon oxide layer on the substrate, plasma treating the silicon oxide layer, depositing a silicon nitride layer on the silicon oxide layer by an ALD process, and thermal annealing the substrate, wherein the formed silicon oxide layer and the silicon nitride layer has a total thickness less than 30 .ANG. utilized as a gate dielectric layer in a gate structure.