Characterization Methods for BTI Degradation and Associated Gate Insulator Defects

In this chapter, different characterization methods are discussed to determine BTI degradation of MOSFET parameters and to directly estimate the pre-existing and generated gate insulator defects responsible for BTI. V T shift is obtained from full I D–V G sweeps and also from spot I D measurements at fixed V G; one spot measurements are performed either on-the-fly at stress V G or by dropping down to a lower V G from stress. Impact of measurement delay and mobility degradation on V T extracted from different methods is discussed. Flicker noise method is used to access the density of pre-existing defects for different gate insulator processes. Gated diode or DCIV, charge pumping (CP) and low voltage SILC methods are used to determine trap generation at or near the interface between Si channel and gate insulator. Conventional SILC is used to estimate generation of bulk gate insulator defects. Different artifacts related to improper choice of stress bias and measurement delay are discussed.