The observation of BTI-induced RTN traps in inversion and accumulation modes on HfO2 high-k metal gate 28nm CMOS devices

A comprehensive analysis on the BTI induced RTN traps in high-k(HK) CMOS devices have been investigated in inversion (inv.) and accumulation (acc.) modes. The combination of two modes for RTN measurement provides a wide range of energy window in high-k gate dielectric, in which a simple extraction method of RTN analysis has been adopted to analyze the gate dielectric dual-layer of advanced HK devices. The results show that inversion mode measurement can only identify the RTN traps in the channel region, which is related to the Vth degradation. While, accumulation mode may detect the traps inside the gate-drain overlap region which provides better understanding of GIDL current. This basic understanding is of critical important to the quality development of HK gate dielectrics in advanced CMOS technologies.