Investigation on Hot-Carrier-Induced degradation of STI-nLDMOS with two-step-oxide process for high side application

In this work, the Hot-Carrier-Induced (HCI) degradation mechanism of the 30 V shallow trench isolation (STI) n-type lateral DMOS (nLDMOS) with two-step-oxide process applied in high side application (called as HS-nLDMOS) is investigated. It implies that the R
_on,sp
(on-resistance measured under high side condition) suffers from more damage impact than R
_on,ls
(on-resistance measured under low side condition). Moreover, a shift of the worst stress condition from the maximum substrate current stress condition (I
_submax
) to the maximum gate voltage stress condition (V
_gmax
) is observed when the HS-nLDMOS is evaluated with R
_on,hs
instead of R
_on,ls
. Hence our investigation suggests estimating the degradation of HS-nLDMOS by R
_on,hs
under V
_gmax
stress condition in order to evaluate the exact life of the device.