High Rate Sputter Deposition of Alkali Metal-Containing Precursor Films Useful to Fabricate Chalcogenide Semiconductors

A method of making a chalcogenide semiconductor, comprising the steps of:

• (a) providing a substrate;
• (b) sputtering one or more targets to form a first film on the substrate, said first film comprising at least one alkali metal compound and at least one conductive species and having a thickness in the range from 10 nm to 150 nm, wherein the one or more targets comprise one or more alkali-metal compounds and one or more conductive species, and wherein the atomic ratio of the one or more alkali metal compounds to the one or more conductive species in said one or more targets is in the range from 15:85 to 85:15;
• (c) forming a second film comprising a chalcogenide semiconductor precursor on the first film, wherein the first and second films are formed in amounts such that the alkali metal content of the chalcogenide semiconductor contains up to 2 atomic percent of alkali metal content based on the total composition of the chalcogenide semiconductor and such that a major portion of the alkali metal content of the chalcogenide semiconductor is derived from the first film;
• and
• (d) heat treating the first and second films under conditions effective to convert at least a portion of the first and second films into an alkali metal-containing chalcogenide semiconductor.

A method of making a chalcogenide semiconductor, comprising the steps of:

• (a) providing a substrate;
• (b) forming a chalcogenide semiconductor precursor film on the substrate;
• (c) sputtering one or more targets to form an additional film on the substrate, said additional film comprising at least one alkali metal compound and at least one conductive species, wherein the one or more targets comprise one or more alkali-metal compounds and one or more conductive species, and wherein the atomic ratio of the one or more alkali metal compounds to the one or more conductive species in said one or more targets is in the range from 15:85 to 85:15, and wherein the chalcogenide semiconductor precursor film and the additional film are formed in amounts such that the alkali metal content of the chalcogenide semiconductor contains up to 2 atomic percent of alkali metal content based on the total composition of the chalcogenide semiconductor and such that a major portion of the alkali metal content of the chalcogenide semiconductor is derived from the additional film;
• and
• (d) heat treating the chalcogenide semiconductor precursor film and the additional film under conditions effective to convert at least a portion of the sodium containing film and the chalcogenide semiconductor precursor film into a Na-containing chalcogenide semiconductor.