Patent ID: 7682939

Claim:
A method for producing a group IB-IIIA-VIA quaternary or higher alloy semiconductor film, the method comprising the steps of: (i) providing a metal film comprising a mixture of group IB and group IIIA metals; (ii) heat treating the metal film in the presence of a source of a first group VIA element, said first group VIA element being hereinafter referred to as VIA 1 , under such conditions that the reaction between the group VIA 1 element and the metals of the mixture of the metal film is incomplete and a first film is formed comprising a mixture of at least one binary alloy selected from the group consisting of a group IB-VIA 1 alloy and a group IIIA-VIA 1 alloy; and at least one group IB-IIIA-VIA 1 ternary alloy, (iii) heat treating the first film in the presence of a source of a second group VIA element, said second group VIA element being hereinafter referred to as VIA 2 , under conditions to convert the first film of step (ii) into a second film comprising at least one alloy selected from the group consisting of a group IB-VIA 1 -VIA 2 alloy and a group IIIA-VIA 1 -VIA 2 alloy; and the at least one group IB-IIIA-VIA 1 ternary alloy of step (ii); and (iv) heat treating the second film of step ((iii)) to form a group IB-IIIA-VIA quaternary or higher alloy semiconductor film.