Investigation into HCl improvement by a split-reeessed-gate structure in an STI-based nLDMOSFET

Abstract

In this paper, we propose a Split-Recessed-Gate LDMOS (SRG-LDMOS) which minimizes HCl degradation with negligible increase in specific on-resistance. In SRG-LDMOS structure, the gate poly is split into two parts, the primal gate on the channel and the secondary recessed gate on the STI. This secondary recessed gate is nominally connected to source to minimize the HCl degradation although it is possible to be biased independently. The recessed gate connected to source helps to relax the electric field and decrease the impact ionization generation rate near the channel-side STI edge during the HCl stress.