The metal gate MOS reliability with improved sputtering process for gate electrode

The impacts of the N/sub 2/ introduced reactive sputtering deposition of WN/sub x/ or TiN gate electrodes on the gate leakage current and the dielectric reliability of the metal gate MOS capacitors are investigated. The surface nitridation of the gate dielectric during the reactive sputtering deposition dramatically improves the gate dielectric characteristics, being comparable to those of the poly-Si gate. The activation energy of charge-to-breakdown (Q/sub bd/) of the metal gates is identical with that of the poly-Si gate under the gate injection stress. Under the substrate injection stress, however, the activation energy of the metal gates is lower than that of the poly-Si gate due to the enhanced electron trapping of the metal gates.