Development of a Novel Ultrafast Direct Threshold Voltage $(\hbox{UF-DV}_{T})$ Technique to Study NBTI Stress and Recovery

An ultrafast measurement technique is developed to directly determine threshold voltage shift (Δ
V
_T
) during negative bias temperature instability (NBTI) stress and recovery from the microsecond (μs) timescale. The technique is developed around a measurement setup that integrates ultrafast on-the-fly (UF-OTF) linear drain current (
I
_DLIN
) and ultrafast measure-stress-measure (UF-MSM) setup hardware by a custom microcontroller-based trigger generator. The technique offers an in-built scheme for converting measured
I
_DLIN
degradation (Δ
I
_DLIN
) to conventional (peak
g
_m
based) Δ
V
_T
and alleviates the need for any postprocessing correction. The developed measurement setup is used to obtain and compare time evolution, as well as the oxide field (
E
_OX
) and temperature (
T
) dependence of Δ
V
_T
during NBTI stress, as calculated using different existing methods. Based on the comparison, a simpler and faster single-point drop-down modification of the UF-MSM part of the technique is proposed.