Method for making a charge balanced multi-nano shell drift region for superjunction semiconductor device

摘要

A method is disclosed for making a substantially charge balanced multi-nano shell drift region (MNSDR) for superjunction semiconductor devices atop a base substrate. The MNSDR has numerous concentric nano shell members NSM₁, NSM₂, . . . , NSM_M (M1) of alternating, substantially charge balanced first conductivity type and second conductivity type and with height NSHT. First, a bulk drift layer (BDL) is formed atop the base substrate. A substantially vertical cavity of pre-determined shape and size and with depth NSHT is then created into the top surface of BDL. The shell members NSM₁, NSM₂, . . . , NSM_M are successively formed inside the vertical cavity, initially upon its vertical walls then moving toward its center, so as to successively fill the vertical cavity till a residual space remains therein. A semi-insulating or insulating fill-up nano plate is then formed inside the residual space to fill it up.