Three-dimensional integration schemes for reducing fluorine-induced electrical shorts

Abstract

Dielectric degradation and electrical shorts due to fluorine radical generation from metallic electrically conductive lines in a three-dimensional memory device can be reduced by forming composite electrically conductive layers and/or using of a metal oxide material for an insulating spacer for backside contact trenches. Each composite electrically conductive layer includes a doped semiconductor material portion in proximity to memory stack structures and a metallic material portion in proximity to a backside contact trench. Fluorine generated from the metallic material layers can escape readily through the backside contact trench. The semiconductor material portions can reduce mechanical stress. Alternatively or additionally, a dielectric metal oxide can be employed as an insulating spacer on the sidewalls of the backside contact trench, thereby blocking a diffusion path for fluorine radicals generated from the metallic material of the electrically conductive layers, and preventing electrical shorts between electrically conductive layers and/or a backside contact via structure.