Recovery investigation of NBTI-induced traps in n-MOSFET devices

Abstract

Conducting negative bias temperature instability (NBTI) stress/recovery experiments on n-type metal-oxide-semiconductor-field-effect-transistors (n-MOSFETs), we have been able to reveal the existence of turn around phenomenon during stress phase. At first stage of stress, threshold voltage (Vth) shifts positively, followed later by a negative shift. Furthermore, recovery phase has shown, for the first time, the contribution of three components to Vth shift (ΔVth) in n-MOSFET. One component is permanent (ΔVthP) and dominated by interface traps, created during stress at the Si/SiO2 interface. The other components are oxide traps, generated in the interfacial oxide region. Both traps are positively charged; one is cyclic (ΔVthC), while the other is totally recoverable (ΔVthR).