Isotropic etching of a hemispherical grain silicon layer to improve the quality of an overlying dielectric layer

摘要

A process for creating a storage node structure, for a DRAM capacitor structure, featuring increased storage node surface area, via use of an HSG silicon layer, on an underlying storage node shape, has been developed. The process features the use of an isotropic, buffered HF etch procedure, applied to the HSG silicon layer, to increase the space between the concave and convex features, of the HSG silicon layer. The increased space between the concave and convex features of the HSG silicon layer, allows a capacitor dielectric layer, of uniform thickness, to be formed on the isotopically etched, HSG silicon layer.