Method of self-aligned dielectric wall formation for forksheet application

Abstract

Aspects of the present disclosure provide a method for fabricating a forksheet semiconductor structure. For example, the method can include forming on a substrate a multi-layer stack including first and second semiconductor layers stacked over one another alternately, forming a cap layer over the multi-layer stack, forming a mandrel structure from the multi-layer stack and the cap layer, forming a fill material that surrounds the mandrel structure and has a top surface level with a top of the mandrel structure, partially recessing the cap layer to uncover opposite inner sidewalls of the fill material, forming sidewall spacers on the opposite inner sidewalls, directionally etching the multi-layer stack to define an insulation wall trench using the sidewall spacers as an etch mask, and forming an insulation material within the insulation wall trench to form an insulation wall that separates the multi-layer stack into insulated first and second multi-layer stacks.