Patent ID: 8853059

Claim:
A method for selenizing a Cu—In—Ga precursor film at high temperatures comprising: forming the Cu—In—Ga precursor film on a substrate; thereafter, heating the substrate to a first temperature between about 350 C and about 450 C in an inert atmosphere at a pressure between 1 atmosphere and 2 atmospheres for a time sufficient to achieve temperature uniformity; thereafter, exposing the Cu—In—Ga precursor to a source of selenium at the first temperature in an atmosphere having a pressure of between 600 Torr and 700 Torr gas for a first period of time sufficient to partially selenize the precursor film; thereafter, heating the substrate to a second temperature between about 450 C and about 550 C in an inert atmosphere at a pressure between 1 atmosphere and 2 atmospheres for a time sufficient to achieve temperature uniformity; thereafter, exposing the Cu—In—Ga precursor to the source of selenium at the second temperature in an atmosphere having a pressure of between 600 Torr and 700 Torr for a second period of time sufficient to further selenize the precursor film; and thereafter, heating the substrate to a third temperature between about 550 C and about 650 C in an inert atmosphere at a pressure between 1 atmosphere and 2 atmospheres for a third period of time sufficient to allow Ga migration in the selenized film to influence the Ga distribution through the depth of the film, wherein the heating to a first and second temperature in an inert atmosphere at a pressure between 1 atmosphere and 2 atmospheres decreases the In agglomeration, and wherein the partial selenization of the precursor film secures the In in a selenized state and prevents agglomeration of In.