Patent ID: 7892924
Filing Date: 2011-02-22
Classification: H01L

Abstract:
1. A method for making a substantially charge balanced multi-nano shell drift region (MNSDR) for superjunction semiconductor device atop a base substrate of second conductivity type, the MNSDR having a nano shell set (NSS) with a plurality of concentric nano shell members NSM 1 , NSM 2 , . . . , NSM i , . . . , NSM M (M>1) of alternating, substantially charge balanced first conductivity type and second conductivity type and with height NSHT, the method comprises: a) providing the base substrate and forming a bulk drift layer (BDL) atop; b) creating, into top surface of the BDL, a substantially vertical cavity of pre-determined shape and size and with depth NSHT; c) successively forming inside the vertical cavity, initially upon its vertical walls then moving toward its center, the shell members NSM d) filling up the residual space by forming a semi-insulating or insulating fill-up nano plate therein.