Patent ID: 6048442
Filing Date: 2000-04-11
Classification: H01L,Y02E,Y02P

Abstract:
A method for producing a thin-film light absorbing layer for a thin-film solar cell which comprisesforming a stacked precursor film comprising a copper-gallium alloy layer and an indium layer on a metallic back electrode layer by sputtering, andthen heating the precursor film in an atmosphere of at least one of selenium and sulfur to thereby form a light absorbing layer comprising a Cu-III-VI.sub.2 chalcopyrite multi-element compound semiconductor,wherein said stacked precursor film which comprises a copper-gallium alloy layer and an indium layer is formed by depositing the copper-gallium alloy layer and the indium layer in this order on the metallic back electrode layer by sputtering using (1) copper-gallium alloy targets having different gallium contents, with the gallium content in each copper-gallium alloy target being from 1 to 40% by weight and (2) an indium or indium-selenium alloy target,wherein said thin-film light absorbing layer has a side closest to the metallic back electrode layer and a side closest to an interfacial layer in the solar cell and has a gallium concentration gradient that increases from the side closest to the interfacial layer to the side closest to the metallic back electrode layer.