Study of reliability physics on high-k/metal gate and power devices

This paper focuses attention on MOS interface phenomena. Key issues on Hf-based high-k/metal gate CMOS technology by gate first process for low operational power applications are overviewed. One of the issues is how to control the oxygen vacancy distribution in the high-k/metal gate system, which is requisite for important work-function tuning with EOT scaling. Quantitative understanding of the potential distribution in this system is crucial for obtaining the appropriate V_th in advanced CMOS devices under a low supply voltage operation. In the meantime, breakdown phenomenon and its mechanism of SiC MOS capacitors are studied. Characteristic electric breakdown traces with carpet-bombing-like concaves are observed for Al/SiO₂/SiC MOS capacitors. From TD(Z)DB measurements, the breakdown mechanism is explained and the conduction behaviour during the breakdown can be inferable by elaborating the measurement setup.