On‐resistance reduction in vertical double diffusion metal oxide semiconductor devices using stress applied by thin film

Abstract

This work presents a novel method of reducing on-resistance (R on) in vertical double diffusion metal oxide semiconductor (VDMOS) devices using external stress. By electrodepositing a layer of nickel (Ni) film onto the surface of drain pad, intrinsic film stress is applied on the VDMOS chip. The experiment results show that R on was reduced by 1.7, 2.4, 4.5, 8.3 and 10.5% when the film stresses were 39.2, 49.3, 61.7, 71.6 and 80.3 MPa, respectively. Moreover, thermal stress between Ni film and VDMOS chip can further reduce R on when the temperature increases. Compared with conventional methods for R on reduction, this method is independent of fabrication process of VDMOS devices and capable of controlling accurately the applied stress.