Understanding Frequency Dependence of Trap Generation Under AC Positive Bias Temperature Instability Stress in Si n-FinFETs

Abstract

In this paper, the frequency (f) dependence of trap generation in Si n-channel fin field-effect transistors (n-FinFETs) under AC positive bias temperature instability (PBTI) stress is investigated by fast direct-current current-voltage (DCIV) method and the discharging-based multi-pulse energy profiling (DMP) technique. The experimental results show that both interface trap generation ( $\Delta $ NIT) and bulk trap generation ( $\Delta $ NOT) of n-FinFET under AC PBTI stress are almost independent of the AC frequency. However, further analysis shows that $\Delta $ NOT consists of shallow traps near EC of Si and deep traps near Ev of Si. Moreover, about 22% of deep traps decrease with shallow traps increasing under 1.4V overdrive voltage (Vov) at 125°C with AC bias frequency increasing from 10 Hz to 1 MHz.

Keywords

• Reliability
• positive bias temperature instability (PBTI)
• AC
• Si FinFETs
• trap generation
• energy distribution