Remote reactant reservoirs for codeposition with variable melt area evaporant flux control

A method, comprising:

• operating a reactant precursor vapor flux control and delivery system located in a vacuum deposition chamber comprising:
• conveying melted liquid feedstock from a feedstock buffer reservoir to an evaporation source reservoir remotely mechanically liquid level coupled to the feedstock buffer reservoir, the evaporation source reservoir having a cavity shape that defines an evaporant liquid pool surface area that increases as a function of fill level of the evaporation source reservoir;
• and
• conveying reactant precursor vapor from the evaporation source reservoir to a deposition zone,
• wherein the feedstock buffer reservoir is located in a lower-temperature zone where a reactant precursor is liquid and the evaporation source reservoir is located in a higher-temperature zone where the reactant precursor has a desired vapor pressure, wherein the lower-temperature zone has a first temperature that is lower than a second temperature of the higher-temperature zone,
• wherein a fill level of melted liquid feedstock in the feedstock buffer reservoir is substantially equal to a fill level of melted liquid feedstock in the evaporation source reservoir.