Ge MOS characteristics with CVD HfO/sub 2/ gate dielectrics and TaN gate electrode

In this paper, we report for the first time Ge MOS characteristics with ultra thin rapid thermal CVD HfO/sub 2/ gate dielectrics and TaN gate electrode. Using the newly developed pre-gate cleaning and NH/sub 3/-based Ge surface passivation, the TaN/HfO/sub 2//Ge gate stack with EOT of 12.9 /spl Aring/ exhibits excellent leakage current density of 6 mA/cm/sup 2/ @Vg=1V and interface state density (D/sub it/) of 8/spl times/10/sup 10//cm/sup 2/-eV. Both D/sub it/ and CV hysteresis of Ge MOS are improved significantly with NH/sub 3/ surface treatment. We also study the effects of post-deposition anneal and investigate the conduction mechanism of TaN/HfO/sub 2//Ge gate stack.