Transitional dielectric layer to improve reliability and performance of high dielectric constant transistors

A method of fabricating a dielectric for use as a transistor gate dielectric in a semiconductor fabrication process, comprising:

• forming a transitional dielectric film overlying a residual oxide film overlying a semiconductor substrate, wherein the transitional dielectric film includes a plurality of transitional dielectric layers, wherein a dielectric constant of a layer proximal to an upper portion of the transitional dielectric film is greater than a dielectric constant of a transitional dielectric layer proximal to an interface with residual oxide film;
• and
• forming a high K dielectric overlying the transitional dielectric film, wherein a dielectric constant of the high K dielectric is greater than 3.9.

A gate dielectric structure in a semiconductor device, comprising:

• a transitional dielectric film overlying a semiconductor substrate, wherein a dielectric constant at an upper surface of the film exceeds a dielectric constant proximal the semiconductor substrate;
• and
• a high K dielectric film overlying transitional dielectric, wherein a dielectric constant of the high K dielectric is greater than a dielectric constant of silicon dioxide.