Oxygen inserted si-layers for reduced contact implant outdiffusion in vertical power devices

Abstract

A semiconductor device includes a gate trench extending into a Si substrate, a body region in the Si substrate, the body region including a channel region which extends along a sidewall of the gate trench, a source region in the Si substrate above the body region, a contact trench extending into the Si substrate and separated from the gate trench by a portion of the source region and a portion of the body region, the contact trench being filled with an electrically conductive material which contacts the source region at a sidewall of the contact trench and a highly doped body contact region at a bottom of the contact trench, and a diffusion barrier structure formed along the sidewall of the contact trench and disposed between the highly doped body contact region and the channel region, the diffusion barrier structure including alternating layers of Si and oxygen-doped Si.