Measurement considerations for evaluating BTI effects in SiC MOSFETs

In this paper, we review the phenomenon of bias-temperature instability (BTI) in SiC MOS devices, with an emphasis on the effects of metrology. The complex behavior of the charge trapping mechanism responsible for VT instability requires careful consideration of measurement conditions and precise control of the associated parameters to produce meaningful results. Preconditioning the devices to be tested, as well as making faster measurements, will elicit the truest response. Any bias interruption or delay between stressing and measurement will produce a large deterioration in the original VT drift caused by the stressing, though this can be effectively counteracted by briefly reapplying the stress bias before measurement.