Nitrogen concentration effects and performance improvement of MOSFETs using thermally stable HfO/sub x/N/sub y/ gate dielectrics

The effects of nitrogen concentration on the material and electrical properties of HfO/sub x/N/sub y/ gate dielectrics were investigated. Higher concentration of nitrogen provides better thermal stability while sacrificing mobility. However, with high temperature forming gas (F/G) anneal, HfO/sub x/N/sub y/ showed improved peak mobility (/spl sim/250 cm/sup 2//eV) as well as superior thermal stability.