Abstract: It is advantageous to create texture at the surface of a photovoltaic cell to reduce reflection and increase travel length of light within the cell. A method is disclosed to create texture at the surface of a silicon body by reacting a silicide-forming metal at the surface, where the silicide-silicon interface is non-planar, then stripping the silicide, leaving behind a textured surface. Depending on the metal and the conditions of silicide formation, the resulting surface may be faceted. The peak-to-valley height of this texturing will generally be between about 300 and about 5000 angstroms, which is well-suited for use in photovoltaic cells comprising a thin silicon lamina.

Abstract: Ion implanters are especially suited to meet process dose and energy demands associated with fabricating photovoltaic devices by ion implantation followed by cleaving.

Abstract: A method to fabricate a photovoltaic device includes forming first and second contact regions at the first surface of a semiconductor donor body. A cleave plane may be formed by implanting ions into the donor body, and a lamina that includes the contact regions is cleaved from the donor body at the cleave plane. The first surface of the lamina may be contacted with a temporary support and fabricated into a photovoltaic device, wherein the lamina comprises the base of the photovoltaic device.

Abstract: A sequence of series-connected transformers for transmitting power to high voltages incorporates an applied voltage distribution to maintain each transformer in the sequence below its withstanding voltage.

Abstract: A structure to provide a Zener diode to avoid shunt formation is disclosed. An undoped or lightly doped monocrystalline thin semiconductor lamina is cleaved from a donor body which is not permanently affixed to a support element. The lamina may be annealed at high temperature to remove damage from a prior implant. At least one aperture is formed through the lamina, either due to flaws in the cleaving process, or intentionally following cleaving. Heavily doped amorphous silicon layers having opposite conductivity types are deposited on opposite faces of the lamina, one forming the emitter and one a base contact to a photovoltaic cell, while the lamina forms the base of the cell. The heavily doped layers contact in the aperture, forming a Zener diode. This Zener diode prevents formation of shunts, and may behave as a bypass diode if the cell is placed under heavy reverse bias, as when one cell in a series string is shaded while the rest of the string is exposed to sun.

Abstract: A method for producing a lamina from a donor body includes implanting the donor body with an ion dosage and heating the donor body to an implant temperature during implanting. The donor body is separably contacted with a susceptor assembly, where the donor body and the susceptor assembly are in direct contact. A lamina is exfoliated from the donor body by applying a thermal profile to the donor body. Implantation and exfoliation conditions may be adjusted in order to maximize the defect-free area of the lamina.

Abstract: A method for producing a lamina from a donor body includes implanting the donor body with an ion dosage and separably contacting the donor body with a susceptor assembly, where the donor body and the susceptor assembly are in direct contact. A lamina is exfoliated from the donor body, and a deforming force is applied to the lamina or to the donor body to separate the lamina from the donor body.

Abstract: A system for simultaneously treating multiple workpieces is configured with treatment sites, configured to hold respective workpieces, fixed on a rotatable base. Treatment stations are equipped with respective active components operable simultaneously to treat respective workpieces identically on respective aligned treatment sites. For loading and unloading the treatment sites are rotated through distinct loading and unloading stations of the treatment stations which allow loading of a second batch while a first batch is being unloaded.

Abstract: A d. c. charged particle accelerator comprises accelerator electrodes separated by insulating spacers defining acceleration gaps between adjacent pairs of electrodes. Individually regulated gap voltages are applied across each adjacent pair of accelerator electrodes. In an embodiment, direct connections are provided to gap electrodes from the stage points of a multistage Cockcroft Walton type voltage multiplier circuit. The described embodiment enables an ion beam to be accelerated to high energies and high beam currents, with good accelerator stability.

Abstract: A d. c. charged particle accelerator comprises accelerator electrodes separated by insulating spacers defining acceleration gaps between adjacent pairs of electrodes. Individually regulated gap voltages are applied across each adjacent pair of accelerator electrodes. In embodiments, the individually regulated gap voltages are generated by electrically isolated alternators mounted on a common rotor shaft driven by an electric motor. Alternating power outputs from the alternators provide inputs to individual regulated d. c. power supplies to generate the gap voltages. The power supplies are electrically isolated and have outputs connected in series across successive pairs of accelerator electrodes. The described embodiment enables an ion beam to be accelerated to high energies and high beam currents, with good accelerator stability.

Abstract: It is advantageous to create texture at the surface of a photovoltaic cell to reduce reflection and increase travel length of light within the cell. A method is disclosed to create texture at the surface of a silicon body by reacting a silicide-forming metal at the surface, where the silicide-silicon interface is non-planar, then stripping the silicide, leaving behind a textured surface. Depending on the metal and the conditions of silicide formation, the resulting surface may be faceted. The peak-to-valley height of this texturing will generally be between about 300 and about 5000 angstroms, which is well-suited for use in photovoltaic cells comprising a thin silicon lamina.

Abstract: A semiconductor assembly is described in which a support element is constructed on a surface of a semiconductor lamina. Following formation of the thin lamina, which may have a thickness about 50 microns or less, the support element is formed, for example by plating, or by application of a precursor and curing in situ, resulting in a support element which may be, for example, metal, ceramic, polymer, etc. This is in contrast to a rigid or semi-rigid pre-formed support element which is affixed to the lamina following its formation, or to a donor wafer from which the lamina is subsequently cleaved. Fabricating the support element in situ may avoid the use of adhesives to attach the lamina to a permanent support element; such adhesives may be unable to tolerate processing temperatures and conditions required to complete the device.

Abstract: Multiple control electrodes are provided asymmetrically within the plasma chamber of an ion source at respective positions along the length of the plasma chamber. Biasing the control electrodes selectively can selectively enhance the ion extraction current at adjacent positions along the length of the extraction slit. A method of generating an ion beam is disclosed in which the strengths of the transverse electric fields at different locations along the length of the plasma chamber are controlled to modify the ion beam linear current density profile along the length of the slit. The method is used for controlling the uniformity of a ribbon beam.

Abstract: A bonding apparatus and method holds first and second bodies peripherally, one above the other, on respective shelves. A lower heat-transfer body is configured to lift the first body from below and press the first and second bodies against an upper heat-transfer body to enable bonding between the first and second bodies.

Abstract: A semiconductor assembly is described with a thin metal oxide layer interposed between a transparent conductive oxide and an amorphous silicon layer, along with methods for making this structure. The metal oxide layer has a refractive index or range of refractive indices intermediate between that of the transparent conductive oxide and the amorphous silicon layer, and thus tends to reduce reflection at the interface. Such a layer can be used at the light-facing surface of a light-sensitive device such as a photovoltaic cell to maximize the amount of incident light entering the cell. Titanium oxide is a suitable metal oxide, and has a refractive index between those of silicon and of both indium tin oxide and aluminum-doped zinc oxide, two common transparent conductive oxides.

Abstract: A method is described to create a thin semiconductor lamina adhered to a ceramic body. The method includes defining a cleave plane in a semiconductor donor body, applying a ceramic mixture to a first face of the semiconductor body, the ceramic mixture including ceramic powder and a binder, curing the ceramic mixture to form a ceramic body, and cleaving a lamina from the semiconductor donor body at the cleave plane, the lamina remaining adhered to the ceramic body. Forming the ceramic body this way allows outgassing of volatiles during the curing step. Devices can be formed in the lamina, including photovoltaic devices. The ceramic body and lamina can withstand high processing temperatures. In some embodiments, the ceramic body may be conductive.

Abstract: Fabrication of a photovoltaic cell comprising a thin semiconductor lamina may require additional processing after the semiconductor lamina is bonded to a receiver. To minimize high-temperature steps after bonding, the p-n junction is formed at the back of the cell, at the bonded surface. In some embodiments, the front surface of the semiconductor lamina is not doped or is locally doped using low-temperature methods. The base resistivity of the photovoltaic cell may be reduced, allowing a front surface field to be reduced or omitted.

Abstract: A method is provided to adhere a lamina to a receiver element using a glass frit mixture. A donor body having a previously defined cleave plane and a receiver element are provided. The glass frit mixture is applied to either the donor body or the receiver element, or both, and is first dried to drive off solvents, then heated to burn out organics. If the glass frit mixture is applied to the receiver, the receiver element and glass frit mixture may be heated to the flow temperature of the frit. Following burn out of organics, the glass frit mixture will undergo no additional outgassing or densification. The receiver element and the donor body are then juxtaposed, the glass frit layer between them. The structure is heated further to permanently adhere the surfaces and to cleave a lamina from the donor body at the cleave plane. A device such as a photovoltaic cell is fabricated, the cell comprising the lamina.

Abstract: Embodiments of the present invention provide for a system for accelerating hydrogen ions. A hydrogen generator holding a supply of water is configured to generate a flow of hydrogen gas from the supply of water. An ion source structure is configured to generate a plurality of hydrogen ions from the flow of hydrogen gas. An accelerator tube is configured to accelerate the plurality of hydrogen ions. The supply of water has an isotopic ratio of deuterium that is smaller than the isotopic ratio of deuterium in Vienna Standard Mean Ocean Water.

Abstract: A semiconductor assembly is described in which a support element is constructed on a surface of a semiconductor lamina. Following formation of the thin lamina, which may have a thickness about 50 microns or less, the support element is formed, for example by plating, or by application of a precursor and curing in situ, resulting in a support element which may be, for example, metal, ceramic, polymer, etc. This is in contrast to a rigid or semi-rigid pre-formed support element which is affixed to the lamina following its formation, or to a donor wafer from which the lamina is subsequently cleaved. Fabricating the support element in situ may avoid the use of adhesives to attach the lamina to a permanent support element; such adhesives may be unable to tolerate processing temperatures and conditions required to complete the device.