Oxide Trap-Induced RTS in MOSFETs

Random telegraph signals (RTS) have been used as a technique for gate oxide defect analyses for the last few decades. The time required by a gate oxide defect to capture and emit an inversion layer carrier can be used to extract the defect energy parameters. The RTS behavior measured at different temperatures can provide sufficient information to determine the structure and physical nature of the responsible defects. In addition, an RTS simulation tool is developed that can successfully reconstruct the RTS traces based on the trap parameters related to the defects. Application of electrical stress results in additional RTS in the output signal, which is believed to be the result of Si–Si bond breakage and creation of hole traps, or reactivation of passivated traps. Stressing the MOSFETs has also resulted in random activation and deactivation of oxide traps. This chapter focuses on the theoretical background of RTS in MOSFETs, sample setup for RTS measurements, data analyses, advantages, and limitations of using RTS to characterize defects.