Manganese-Based Self-Forming Barrier Layer for Stack-Integrated Metasurface Devices and Sequential Damascene Manufacturing

A method to manufacture an optical metasurface, comprising:

• forming an optical reflector layer;
• forming an interconnect layer above the optical reflector layer;
• and
• forming a resonator layer with an array of optical resonators that extend vertically with respect to the optical reflector layer, the resonator layer comprising conductive optical structures including stack-integrated metallic optical elements arranged to define a plurality of gaps therebetween, wherein forming each stack-integrated metallic optical element comprises at least:
• forming a base metallic optical element via a damascene process with a tantalum-based barrier layer,
• forming a first stacked metallic optical element on top of the base metallic optical element via a subsequent damascene process with a manganese-based self-forming barrier (Mn-SFB), and
• annealing to cause manganese associated with the Mn-SFB to form a manganese-silicon-oxide layer (MnSiOx) on sidewalls of the first stacked metallic optical element and to cause copper to join the base metallic optical element and the first stacked metallic optical element;
• and
• positioning a tunable dielectric material that has a tunable refractive index within the gaps.

A method to form a stack-integrated metallic optical element comprising:

• forming a base metallic optical element via a damascene process with a tantalum-based barrier layer;
• and
• forming a first stacked metallic optical element on top of the base metallic optical element via a subsequent damascene process, wherein the subsequent damascene process includes:
• depositing a manganese-based self-forming barrier (Mn-SFB), and
• annealing the Mn-SFB to form a manganese-silicon-oxide layer (MnSiOx) on sidewalls of the first stacked metallic optical element and to cause copper to join the base metallic optical element and the first stacked metallic optical element.