Abstract: Methods, tools and systems for full characterization of thin and ultra-thin layers employed in advanced semiconductor device structures are disclosed.

Abstract: Methods, tools and systems for full characterization of thin and ultra-thin layers employed in advanced semiconductor device structures are disclosed.

Abstract: A thin film solar cell structure is disclosed, the solar cell structure comprising a CdSexS(1-x) junction partner layer forming a hetero-interface with a CdSeyTe(1-y) absorber layer, where the value of “x” is larger than or equal to zero and smaller than or equal to about 0.5, and where the value of “y” is larger than or equal to about 0.7 and smaller than or equal to about 0.8. A method of fabricating a solar cell is also disclosed, the method comprising: depositing a CdSexS(1-x) junction partner film, and providing a CdSeyTe(1-y) absorber layer to form a hetero-interface between the CdSexS(1-x) junction partner film and the CdSeyTe(1-y) absorber layer, wherein a value of “x” is larger than or equal to zero and smaller than or equal to about 0.5, and wherein a value of “y” is larger than or equal to about 0.7 and smaller than or equal to about 0.8.

Abstract: A roll-to-roll rapid thermal processing (RTP) tool with multiple chambers for forming a solar cell absorber by reacting a precursor layer on a continuous flexible workpiece. The RTP tool includes an elongated housing having a heating chamber with a predetermined temperature profile, a supply chamber and a receiving chamber. The heating chamber includes a small process gap in which the precursor layer is reacted with a Group VIA material to form an absorber layer. The continuous flexible workpiece is unrolled and advanced from the supply chamber into the heating chamber, and the processed continuous flexible workpiece is taken up and rolled in the receiving chamber.

Abstract: A method of forming an ohmic contact and electron reflector on a surface of a CdTe containing compound film as may be found, for example in a photovoltaic cell. The method comprises forming a Cd-deficient, Te-rich surface region at a surface of the CdTe containing compound film; exposing the Cd-deficient surface region to an electron reflector forming material; forming the electron reflector; and laying down a contact layer over the electron reflector layer. The solar cell so produced has a Cd-deficient region which is converted to an electron reflector layer on the surface of a CdTe absorber layer, and an ohmic contact. A Cd/Te molar ratio within the Cd-deficient region decreases from 1 at an interface with the CdTe absorber layer to a value less than 1 towards the ohmic contact.

Abstract: A method of making a back contact to a Group IIB-VIA compound layer employed in a device such as a solar cell and in particular a CdTe solar cell. The method involves deposition of a contact buffer layer comprising an ionic conductor over a surface of a CdTe film, which is the absorber of the solar cell. A highly conductive contact layer is deposited over the contact buffer layer. In some examples, the compound device is a device such as a solar cell and in particular a CdTe solar cell in a sub-strate configuration or structure. The method involves deposition of a contact buffer layer comprising an ionic conductor on a surface of a highly conductive contact layer. A CdTe film, which is the absorber layer of the solar cell is then deposited over the contact buffer layer.

Abstract: An evaporation tool for forming a dopant structure on a front surface of a continuous workpiece, wherein the front surface includes a precursor layer to form Group IBIIIAVIA absorbers for solar cells and the dopant structure is used to introduce dopants into the precursor layer. The tool includes at least a first vapor source station to deposit a Group VIA material, such as Se, and a second vapor station to deposit a dopant material, such as Na, onto the continuous workpiece. A moving assembly of the tool holds and moves the continuous workpiece within the tool by feeding the continuous workpiece from a first end and taking up from a second end of the tool. A support assembly of the tool contacts a back surface of the continuous workpiece to remove the heat from and apply tension to the continuous workpiece during the process.

Abstract: Methods and apparatus are described for electrodeposition of Group IIB-VIA materials out of electrolytes comprising Group IIB and Group VIA species onto surfaces of workpieces. In one embodiment a method of electrodeposition is described wherein the control of the process is achieved by measuring an initial value of the electrodeposition current at the beginning of the process and adding Group VIA species into the electrolyte to keep the electrodeposition current substantially constant, such a within +/?10% of the initial value throughout the deposition period. In another embodiment an apparatus comprising multiple deposition chambers are described, each deposition chamber containing an anode and a workpiece, and wherein two thirds of the deposition chambers within the apparatus contain anodes comprising a substantially pure Group VIA element in their composition, and the rest of the deposition chambers contain anodes free from any Group VIA element in their composition.

Abstract: A method of fabricating a solar cell involves electroplating a Group IIB-VIA material as a first or sub-layer over a junction partner layer, and then forming a second layer, also of a Group IIB-VIA material over the sub-layer. Both the sub-layer and the second layer comprise Te. The electroplating is performed at relatively low temperatures, as for example, below 100° C. Forming the sub-layer by low temperature electroplating produces a small grained compact film that protects the interface between the sub-layer and the junction partner during the formation of the second layer. The second layer may be formed by physical vapor deposition or ink deposition. A solar cell has a first layer of a stoichiometric Group IIB-VIA material formed on a CdS film, and a second layer of a Group IIB-V1A material. Both the first and second layers contain Te. The first layer may comprise CdTe with a grain size small than 0.5 microns and the second layer may comprise CdTe with a grin size in the range of 1-5 microns.

Abstract: An electrochemical co-deposition method and solution to plate uniform, defect free and smooth (In,Ga)—Se films with repeatability and controllable molar ratios of (In,Ga) to Se are provided. Such layers are used in fabrication of semiconductor and electronic devices such as thin film solar cells. In one embodiment, the present invention provides an alkaline electrodeposition solution that includes an In salt, a Se acid or oxide, a tartrate salt as complexing agent for the In species, and a solvent to electrodeposit an In—Se film possessing sub-micron thickness on a conductive surface.

Abstract: Precursor layers and methods of forming Group IBIIIAVIA solar cell absorbers with bandgap grading using such precursor layers are described. The Group IBIIIAVIA absorber includes a top surface with a Ga/(Ga+In) molar ratio in the range of 0.1-0.3. The Group IBIIIAVIA solar cell absorber is formed by reacting the layers of a multilayer material structure which includes a metallic film including Cu, In and Ga formed on a base, a layer of Se formed on the metallic film, and a second metallic layer substantially including Ga formed on the layer of Se.

Abstract: A multilayer structure to form absorber layers for solar cells. The multilayer structure includes a base comprising a contact layer on a substrate layer, a first layer on the contact layer, and a metallic layer on the first layer. The first layer includes an indium-gallium-selenide film and the gallium to indium molar ratio of the indium-gallium-selenide film is in the range of 0 to 0.8. The metallic layer includes gallium and indium without selenium. Additional selenium is deposited onto the metallic layer before annealing the structure for forming an absorber.

Abstract: A method of forming a Group IBIIIAVIA solar cell absorber, which includes a top surface region of less than or equal to 300 nm depth. The Ga/(Ga+In) molar ratio within the top surface region is in the range of 0.1-0.3. The Group IBIIIAVIA solar cell absorber is formed by reacting the layers of a multilayer material structure which includes a metallic film including at least Cu and In formed on a base, a separator layer including Se is formed on the metallic film, a metallic source layer substantially including Ga formed on the separator layer, and a cap layer substantially including Se formed on the source layer.

Abstract: Processes and apparatus are described that form a solar cell absorber on a surface of a workpiece by reacting a precursor layer disposed on the surface of the workpiece with an absorber constituent vapor in a heating chamber. The absorber constituent material is delivered from an absorber constituent material delivery system in molten form into a container in the heating chamber and vaporized to be used during the reaction.

Abstract: A method and a system are provided for forming planar absorber layers or structures by planarizing and reacting precursor layers in a reactor. A precursor structure is first formed over the front surface of a foil substrate and then planarized through application of pressure by a smooth surface while heated to a first temperature range to obtain a planar layer. The planar layer may be only partially reacted. The planar layer is further reacted at a second temperature range to form a fully or completely reacted planar absorber layer. The planar absorber layer may include at least one Group IB material, at least one Group IIIA material and at least one Group VIA material. The planar absorber layer may be a Group IBIIIAVIA compound layer.

Abstract: Described is a continuous electroless deposition method and a system to form a solar cell buffer layer with a varying composition through its thickness are provided. The composition of the buffer layer is varied by varying the composition of a chemical bath deposition solution applied onto an absorber surface on which the buffer layer with varying composition is formed. In one example, the buffer layer with varying composition includes a first section containing CdS, a second section containing CdZnS formed on top of the already deposited CdS, and a third section containing ZnS is formed on the second section All the process steps are applied in a roll-to-roll fashion. In another example, a transparent conductive layer including a first transparent conductive film such as aluminum doped zinc oxide and a second transparent conductive film such as indium tin oxide is deposited over the buffer layer with the varying composition.

Abstract: The present inventions relate to methods and apparatus for detecting and mechanically removing defects and a surrounding portion of the photovoltaic layer and the substrate in a thin film solar cell such as a Group IBIIIAVIA compound thin film solar cell to improve its efficiency.

Abstract: The embodiments of the present invention provide a defect detection process and apparatus to detect defects in solar cell structures. During the process, an input signal from a signal source is applied to a top surface of a transparent conductive layer of a solar cell structure. In response to the input signal, an output signal is generated from a predetermined area of the top surface and detected by a defect detector. The output signal carrying the defect position information is transmitted to a computer and registered in a database. With the position information, an injector is driven to the defect location to apply an insulator to passivate the defect. A finger pattern layer may be formed over the predetermined area after completing the defect detection and passivation processes.

Abstract: An electrochemical deposition method to form uniform and continuous Group IIIA material rich thin films with repeatability is provided. Such thin films are used in fabrication of semiconductor and electronic devices such as thin film solar cells. In one embodiment, the Group IIIA material rich thin film is deposited on an interlayer that includes 20-90 molar percent of at least one of In and Ga and at least 10 molar percent of an additive material including one of Cu, Se, Te, Ag and S. The thickness of the interlayer is adapted to be less than or equal to about 20% of the thickness of the Group IIIA material rich thin film.

Abstract: A system and method of forming a thin film solar cell with a metallic foil substrate are provided. After forming a semiconductor absorber film over the front surface of the metallic foil substrate a back surface of the metallic foil substrate is treated using a material removal process to form a treated back surface in a process chamber. In one embodiment, the material removal process is performed while depositing a transparent conductive layer over the semiconductor absorber film in the process chamber.