A high k dielectric film and methods for forming the same are disclosed. The
high
k material includes two peaks of impurity concentration, particularly nitrogen,
such as at a lower interface and upper interface, making the layer particularly
suitable for transistor gate dielectric applications. The methods of formation
include low temperature processes, particularly CVD using a remote plasma generator
and atomic layer deposition using selective incorporation of nitrogen in the cyclic
process. Advantageously, nitrogen levels are tailored during the deposition process
and temperatures are low enough to avoid interdiffusion and allow maintenance of
the desired impurity profile.