ESD and LU Immunities of LV nMOSFETs by the Drain-Contact Variations

Abstract

The non-uniform turned-on issue of a multi-finger GGnMOS is deeply affect the ESD robustness. This paper introduces a drain-side engineering: by removing the drain contacts to increase the Ron value of a GGnMOS. However, after the actual systematic testing, it can be concluded that removing the drain contacts will obviously decrease the ESD capability and this way is not good for the ESD ability. The It2 value in the Type-1.1 DUT becomes only 56% of the reference group (Ref. DUT). The It2 value will increase as along with the contact number to increase. Meanwhile, the layout pattern of the contacts concentrated around the both ends will have a higher It2 value, i.e., (It2)type2 > (It2)type1, the increasing percentage of It2 values of Type-2 as compared with Type-1 can be up to 8.63%. So, a drain-contact arrangement will strongly affect the device ESD ability.