优化了栅电极溅射工艺的难熔金属栅MOS电容的性能

论述了通过优化难熔金属栅电极的溅射工艺及采用适当的退火温度修复损伤来提高3nm栅氧W/TiN叠层栅MOS电容的性能.实验选取了合适的TiN厚度来减小应力,以较小的TiN溅射率避免溅射过程对栅介质的损伤,并采用了较高的N2/Ar比率在TiN溅射过程中进一步氮化了栅介质.实验得到了高质量的C-V曲线,并成功地把Nss(表面态密度)降低到了8×1010/cm2以下,达到了与多晶硅栅MOS电容相当的水平.

Characteristics of Refractory Metal Gate MOS Capacitor with Improved Sputtering Process for Gate Electrode

The technique to improve the performance of W/TiN stacked gate MOS capacitor with 3nm gate oxide is reported by optimizing the sputtering process of a refractory metal gate electrode and adopting a proper anneal temperature to eliminate the damages. Specific methods involved in the optimization of sputtering process include:selecting a proper TiN thickness to reduce stresses;using a smaller sputtering rate to suppress the damages to gate dielectric and adopting a higher N2/Ar ratio during the TiN sputtering process to further nitride the gate dielectric.With these measures,excellent C-V curves are obtained and surface state density (Nss) is successfully reduced to below 8 × 1010cm-2,which is comparable to the polysilicon gate MOS capacitor.