Isolation edge effect depending on gate length of MOSFET's with various isolation structures

The gate length (L) dependence of the isolation edge effect is investigated for MOSFET's with various isolation structures. We extract the isolation e dge effect for a single L by comparing with an H-shaped gate MOSFET which d id not have any influence from the isolation edges. For shallow trench isolation (STI), the isolation edge effect is enhanced f or L around the onset of the short channel effect (SCE! and is more promine nt for a trench edge with a deeper dip. On the other hand, for the local ox idation of silicon (LOCOS) isolation with an elevated field oxide edge (i.e ., the bird's beak), the isolation edge effect operates in the opposite dir ection against the cases of Sn, though it is enhanced around the SGE appear ance point. The L dependence is successfully explained using the charge sharing model w here the charge shared by the mixing effect between the SCE and the (invers e) narrow width effect [(I)NWE] is introduced at the channel corners. The e nhancement of the isolation edge effect results from that the fraction of t he charge shared by the mixing effect depends on L, In addition, the differ ence between STI and LOGOS occurs because the mixing effect for STI is appo site to that for LOCOS.