Patent ID: 8158537

Claim:
A method comprising: depositing a first film layer onto a substrate, wherein the film layer includes one or more of Se, Te and S, and either Cu or one or more of In and Ga, and wherein the one or more of Se, Te and S in the aggregate is less than or equal to 80 atomic percent; depositing a second film layer onto the first film layer, wherein the second film layer comprises Cu if the first film thin contains In and/or Ga, or In and/or Ga if the first film layer contains Cu; depositing a third film layer over the first and second film layers, wherein the third film layer comprises over 20 atomic percent of Se, Te and/or S in the aggregate; annealing the first, second and third deposited film layers at an average heating rate of or exceeding 1 degree Celsius per second; removing excess material from one or more of the first, second, or third film layers, the excess material comprising Cu and one or more of S, Se, or Te; and cooling the annealed first, second and third film layers at an average cooling rate of or exceeding 0.1 degrees Celsius per second.