The Effect of the Subthreshold Slope Degradation on NBTI Device Characterization

A new fast switching NBTI measurement method was introduced based on applying alternating V
_GS
test conditions to determine SS-NBTI results using this new method show that unexpectedly SS decreases (improves) with stress time • It was determined that SS improves during NBTI Stress because device |V
T
| increases effectively moving the V
GS
@ test point to a reduced |I
D
| point • An improvement in the pending NBTI JEDEC test standard was proposed which consists of incrementing the test V
GS
after each stress interval effectively keeping the test point at I
D
(0) - NBTI results from this improved method were in qualitative agreement with post stress I
D
-V
GS
results