Effects of the base layer in Si3N4/SiON stack gate dielectrics, in particular, the physical thickness of the base layer, on the dielectric reliability, MOSFET performance and process controllability are investigated. It is found that the electrical characteristics such as TDDB lifetime as well as the Si3N4 film property in Si3N4/SiON stack dielectrics with the same capacitance oxide equivalent thickness strongly depend on the SiON-base layer thickness. From the TDDB measurements for both stress polarities and from the Si3N4 stoichiometry by the X-ray photoelectron spectroscopy analysis, the optimum SiON-base layer thickness is determined to be approximately 1 nm, in order to obtain longer TDDB lifetime and surperior n-ch MOSFET performance. The obtained results are considered to attribute to the nitrogen profile in the Si3N4/SiON stack dielectrics and the strained layer thickness near SiON/Si interface.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Safety, Risk, Reliability and Quality
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Electrical and Electronic Engineering