Large scale method and furnace system for selenization of thin film photovoltaic materials

A method for fabricating a copper indium diselenide semiconductor film comprising:

• providing a plurality of substrates, each of the substrates having a copper and indium composite structure;
• transferring the plurality of substrates into a furnace, each of the plurality of substrates provided in a vertical orientation with respect to a direction of gravity, the plurality of substrates being defined by a number N, where N is greater than 5;
• introducing a gaseous species including a selenide species and a first carrier gas into the furnace and transferring thermal energy into the furnace to increase a temperature from a first temperature to a second temperature ranging from about 350° C. to about 450° C. to at least initiate formation of a copper indium diselenide film from the copper and indium composite structure on each of the substrates;
• maintaining the temperature at about the second temperature for a period of time;
• removing at least residual selenide species from the furnace;
• introducing a sulfide species into the furnace;
• holding the temperature at a predetermined level to allow the plurality of substrates to reach a predetermined level of temperature uniformity;
• and
• increasing a temperature to a third temperature, the third temperature ranging from about 500° C. to 525° C. or greater while the plurality of substrates are maintained in an environment including a sulfur species to extract at least one selenium species from the copper indium diselenide film.