(JP10135495-A)      The method involves forming a Cu-Ga alloy layer and an In layer, on a metal electrode layer (3) over a glass substrate (2), sequentially by sputtering process. Then, heat treatment of the substrate is carried out in the selenium and/or sulphur environment.    A p type optical absorption layer (4) containing Cu along with II-III-VI group chalcopyrite system compound semiconductor elements and a buffer layer (5) are sequentially laminated on the In layer. The concentration of gallium present in the optical absorption layer increases gradually from the side of buffer layer towards the metal electrode layer.    ADVANTAGE -   Prevents distortion or deformation of substrate. Improves yield. Reduces manufacturing cost by using glass substrate.    (US6048442-A)      Producing a thin film absorbing layer for a solar cell comprises: (a) forming a stacked precursor film of Cu-Ga alloy and an In layer on a metallic back electrode by sputtering, then (b) heating in an atmosphere of at least S or Se to form a Cu-III-VI2 chalcopyrite multi-element compound semiconductor layer. The stacked precursor film is formed by depositing Cu-Ga first and then In. The light absorbing layer has a Ga concentration gradient which increases from the side closest to an interfacial layer in the solar cell to the side closest to the metallic back electrode. Also claimed (II) is the method as (I) in which during sputtering at least one Cu-Ga alloy target is used with an optional Cu target. The Cu-Ga targets have different Ga content in the range 1 - 40 wt% Ga, and an In or In-Se target. Also claimed is the equipment for the methods comprising a sputtering part for deposition of the films on a metallic back element formed on soda-lime float glass.    USE -   Fabrication of solar cells.    ADVANTAGE -   Cheaper low temperature melting soda lime glass substrates can be used. The thin film light absorbing layer is prevented from peeling off other layers.    (US6092669-A)      Producing a thin film absorbing layer for a solar cell comprises: (a) forming a stacked precursor film of Cu-Ga alloy and an In layer on a metallic back electrode by sputtering, then (b) heating in an atmosphere of at least S or Se to form a Cu-III-VI2 chalcopyrite multi-element compound semiconductor layer. The stacked precursor film is formed by depositing Cu-Ga first and then In. The light absorbing layer has a Ga concentration gradient which increases from the side closest to an interfacial layer in the solar cell to the side closest to the metallic back electrode. Also claimed (II) is the method as (I) in which during sputtering at least one Cu-Ga alloy target is used with an optional Cu target. The Cu-Ga targets have different Ga content in the range 1 - 40 wt% Ga, and an In or In-Se target. Also claimed is the equipment for the methods comprising a sputtering part for deposition of the films on a metallic back element formed on soda-lime float glass.    USE -   Fabrication of solar cells.    ADVANTAGE -   Cheaper low temperature melting soda lime glass substrates can be used. The thin film light absorbing layer is prevented from peeling off other layers.