Hello,
Threshold voltage and mobility are affected by the well proximity effect and STI stress, their new equations include new instance parameters: SCA, SCB and SCC considering distances of devices to well edges, which can be extracted when post layout simulation, but theses effects are process dependent. tehy are related to the oxide thickness, the channeldoping profile of the devices...the only consideartion is the average distance between ur well and the active region...
Wish that's help
A+
g@fsos from Gafsa