Method for surface roughness reduction after silicon germanium thin film deposition

A method, comprising:

• providing a planarized substrate having a plurality of CMOS devices formed therein and having at least one metal layer comprising a metal having a softening temperature below about 450 degrees Celsius;
• forming, above the at least one metal layer, a silicon germanium (SiGe) material film, wherein the SiGe material film has a jagged surface comprising projections and indentions extending in a substantially orthogonal direction to the planarized substrate;
• smoothing the jagged surface by applying a chemical mechanical planarization (CMP) process to the jagged surface to reduce variations between the projections and the indentions in the substantially orthogonal direction, and to transform the jagged surface into a substantially planarized surface;
• and
• forming at least one additional layer which, in conjunction with the metal layer and the SiGe material film having the substantially planarized surface, forms a discrete stack of layers operable as a two-terminal memory device.

A memory device, comprising:

• a planarized substrate having a plurality of CMOS devices formed therein;
• a first conductive layer formed on the planarized substrate;
• a SiGe material film formed over the planarized substrate and in contact with the first conductive layer, wherein the SiGe material film has a thickness less than about 350 nm and a planarized surface opposite a surface of the SiGe material film contacting the first conductive layer, wherein the planarized surface is formed at least in part using chemical mechanical planarization (CMP) applied to the SiGe material film as-deposited, and comprises a surface roughness that is less than 1.0 nm rms following application of the CMP;
• a dielectric layer formed over the SiGe film material;
• and
• a second conductive layer formed over the dielectric layer.