NOVELTY - A method of fabricating a light-absorbing thin-film, involves providing raw semiconductor materials; pre-reacting the raw semiconductor materials to form a homogeneous compound semiconductor target material; and depositing the compound semiconductor target material onto a substrate to form a light-absorbing thin-film having a composition the same as composition of the compound semiconductor target material. The compound semiconductor target material is deposited by physical vapor deposition or by magnetron sputtering or by laser ablation.    USE - For fabricating a light-absorbing thin-film used for fabricating a photovoltaic device (claimed) such as photovoltaic solar cells and other devices, used for converting optical energy into electrical energy and for solar cell applications.    ADVANTAGE - The photovoltaic device including the thin film provides a major source of environmentally clean and renewable energy. The copper indium di-selenide (CIS) based semiconductor thin film for photovoltaic device provides a cost effective solution with conversion efficiencies that are sufficient for many practical applications. The process can be used to fabricate high-quality thin-film copper indium di-selenide (CIS)-based semiconductor devices that have photovoltaic effects and are especially adaptable for solar cell applications. The process involves a Reacted Target Physical Deposition (RTPD) method, which provides an alternative path for forming compound semiconductor thin-films. The RTPD method can produce a uniform film with a designated composition while requiring reduced levels of post-deposition processing in comparison to other established fabrication methods. These attributes impart multiple advantages for the design, performance and manufacture of such films for photovoltaic solar cells and other devices. Thin-films fabricated with the RTPD method have improved compositional, chemical and structural uniformity in both profile and in area. As a consequence, properties which are dependent on uniformity can be improved. Thermal and/or chemical post-deposition processes that are conventionally used to approach such uniformity can also be reduced or eliminated. This is beneficial for minimizing interactions between device layers, process simplification and manufacturing cost reduction. The RTPD method allows processing of batch materials at higher temperatures than in conventional approaches. This facilitates better mixing and more complete reaction of the constituents. The method allows improved compositional control of the principal constituents by target composition. This can facilitate band-gap engineering without processing change, e.g. the relationship between composition and the band-gap of the compound semiconductor. The method provides improved doping of the thin-films through pre-doping of targets with, e.g. Na. The method provides more uniform films with fewer vacancies or other performance limiting defects; provides thinner films for reduced materials usage for cost reduction; and provides films with reproducible compositions over larger areas, for higher yield, throughput and low-cost manufacturing. The method exhibits process simplifications including elimination of multi source deposition, monitoring and control and elimination of chemical (e.g. Selenization) and/or thermal post-processing steps. By the RTPD method, CIS or similar films can be produced which are more uniform in composition over area and in profile than can be achieved by current practices. This uniformity imparts a higher performance, reproducibility and manufacturability for CIS solar cells.    DETAILED DESCRIPTION - A method of fabricating a light-absorbing thin-film, involves providing raw semiconductor materials; pre-reacting the raw semiconductor materials to form a homogeneous compound semiconductor target material; and depositing the compound semiconductor target material onto a substrate to form a light-absorbing thin-film having a composition the same as a composition of the compound semiconductor target material. The raw semiconductor materials include II-VI compound semiconductor materials or include I-III-VI compound semiconductor materials. The I-III-VI compound semiconductor materials are selected from Cu-In-Se, Cu-In-Ga-Se and Cu-In-Ga-Se-S. The method further involves providing Al in complete or partial substitution for Ga; or providing Na as a minor constituent along with the I-III-VI compound semiconductor materials; or providing an alkali element other than Na as a minor constituent along with the I-III-VI compound semiconductor materials; or providing F as a minor constituent along with the I-III-VI compound semiconductor materials; or providing a halogen element other than F as a minor constituent along with the I-III-VI compound semiconductor materials. The compound semiconductor target material is deposited by physical vapor deposition or is deposited by magnetron sputtering or is deposited by laser ablation. The step of pre-reacting the raw semiconductor materials includes isolating the raw semiconductor materials at an elevated temperature to establish a structure and bonding profile representative of the deposited thin-film. INDEPENDENT CLAIMS are included for the following:    (1) a light-absorbing thin-film fabricated by the method. The raw semiconductor materials are pre-reacted above a liquidus temperature of the compound semiconductor target material;    (2) a method of fabricating a photovoltaic device, involving: forming a first electrode on a substrate; forming a light absorbing layer on the first electrode, where forming the light absorbing layer includes: providing raw semiconductor materials; pre-reacting the raw semiconductor materials to form homogeneous compound semiconductor target material; and depositing the compound semiconductor target material onto a substrate to form a thin-film having a composition the same as a composition of the compound semiconductor target material; and forming a second electrode over the light absorbing layer; and    (3) a photovoltaic device fabricated by the method.    DESCRIPTION OF DRAWING(S) - The figure shows flowchart illustrating process for fabricating thin film semiconductor device such as photovoltaic device.