Abstract: A method of forming a metallization pattern on a solar cell substrate having an outer layer of a selected dielectric such as silicon nitride, silicon dioxide, or glass, by removing selected portions of the dielectric layer with a laser beam. This laser exposure drives portions of the P/N junction positioned beneath the exposed regions of the substrate more deeply into the substrate. Removal of selected portions of the dielectric layer exposes regions of the silicon substrate on which conductors may be deposited by conventional immersion plating methods. This laser removal of the dielectric layer is effected in an environment substantially free of chemical etching substances. Following removal of the selected portions of the dielectric layer, the substrate is preferably immersed in a buffered oxide etch solution to remove residual silicon dioxide and is then preferably immersed in a high ratio (nitric acid to hydrofluoric acid) etch solution to remove residual silicon nitride.

Abstract: A method of applying metallized contacts to a solar cell substrate, the front surface of which is covered with a dielectric layer. The method involves forming a plurality of apertures extending through the dielectric layer using a laser beam and defining a grid-shaped electrode. The apertures comprise a plurality of microscopically-sized holes that are arranged in a series of rows, with the holes being spaced a relatively short distance from one another. Nickel is plated onto the portions of the substrate exposed through the apertures. The nickel plating is then overcoated with copper which is preferably applied by a contactless light-induced plating process. The copper plating process causes copper to be deposited so that it bridges over the dielectric layer between the holes so as to form an integrated grid electrode structure.

Abstract: A method of forming a metallization pattern on a substrate used in the fabrication of a solar cell or other semiconductor device. The metallization pattern is formed by (1) hydrogen passivating a silicon substrate having a P/N junction formed therein adjacent one surface of the substrate, with a damaged surface layer being formed in conjunction with the hydrogen passivation process, and (2) laser annealing selected portions of said damaged layer whereby said selected portions form a metallization pattern to which selected metals will securely adhere when applied by immersion plating. The foregoing fabrication steps may be performed simultaneously.A layer of material comprising SiO.sub.x may be redeposited on the one surface of the substrate as part of the hydrogen passivation procedure. In the laser annealing step, sections of the redeposited material scanned by the laser beam are ablated and the exposed underlying damaged surface layer is annealed.

Abstract: A solar cell fabrication procedure is described in which a trench is cut in the substrate so as to electrically isolate front and back regions of a flat solar cell. The trench is preferably cut around the perimeter of the rear side of the cell. The trench is preferably formed by an excimer laser which may be used to ablate a trench without diffusing conductive material deeper into the cell.

Abstract: A system for continuously supplying solid silicon particles to an apparatus for growing hollow, tubular crystalline bodies. The system includes a container for storing solid silicon particles, a vibratory, pneumatic, or other device for causing the particles to exit the container through an aperture in the bottom thereof, a receiving chamber coupled with the container for receiving the particles which are dispensed from the container, and means for providing a jet of pressurized fluid in the receiving chamber. The latter is coupled with the crucible of the crystal growth apparatus via a conduit extending up through the center of the crucible.In operation, silicon particles are dispensed from the container, travel into the receiving chamber where they are entrained by the jet of pressurized fluid which drives the particles out of the receiving chamber, through the conduit, and into the crystal growth furnace where they fall back into the molten silicon supported in the crucible.

Abstract: A method of bulk passivating a crystalline or polycrystalline substrate made from silicon, germanium, gallium arsenide or other III-V compounds, and II-VI compounds by exposing the substrate to a fluorine ion beam created by a Kaufman ion source. The Kaufman ion source is controlled so that the intensity of and duration of exposure to the fluorine ion beam is sufficient to bulk passivate the substrate. Preferably, the substrate is preheated to a selected temperature prior to the ion beam exposure.

Abstract: A control system for controlling the operation of an apparatus for growing tubular crystalline bodies. The control system comprises a weight sensor for measuring the weight of the crystal, a length sensor for measuring the length of the crystal, a pressure sensor for measuring the pressure inside the crystal, and a controller coupled to the weight, length and pressure sensors for controlling the operation of the crystal growing apparatus. The controller is coupled to the die heater of the apparatus for controlling the temperature of melt contained in the crucible of the apparatus based on the outputs of the weight, length and pressure sensors. To ensure the wall of the tubular crystalline body is maintained at a substantially uniform thickness, precise measurement of the weight of the body must be made. Compensation is provided by this invention for weight measurement errors that are created by pressure fluctations within the tubular crystalline body.

Abstract: An apparatus and process are disclosed for growing tubular crystalline bodies according to the Edge defined, Film-Fed Growth (EPG) process, wherein the apparatus has at least one exterior passage (240) and at least oen interior passage (245) formed in its crucible die assembly (200) and associated parts, whereby gases introduced into at least one exterior passage (725) will be delivered to the zone located outside the growing crystalline body (900) (i.e. the "exterior" zone ) adjacent to the growth face on the die member (215), and gases introduced into at least one interior passage (720) will be delivered to the zone located inside of the hollow crystalline body (i.e. the "interior" zone) adjacent to the growth face on the die member, whereby the atmosphere in each of the zones may be separately controlled.

Abstract: A process of manufacturing silicon solar cells with efficiencies of between about 12.5% and about 16.0% is described, the method being characterized by forming a P/N junction adjacent the front surface of a silicon substrate, subjecting the front surface of the substrate to a selected plasma surface etch treatment, and then forming a polysilazane coating on the etched front surface by (a) first subjecting the substrate to an ammonia plasma treatment for a predetermined period of time so as to produce hydrogen implantation and (b) subjecting the subtrate to a silane and ammonia plasma treatment to obtain additional hydrogen implantation and formation of a polysilazane (hydrogenated silicon nitride) coating. The polysilazane coating is etched to form a grid electrode pattern. An aluminum coating is applied to the rear side of the substrate so as to form a back electrode. The aluminum coating is heated so as to alloy with the silicon substrate and thereby form an ohmic contact.

Abstract: The invention comprises an improved method of growing crystalline bodies from a melt. The method involves providing (1) a crucible for containing a melt having a plurality of first and second grooves of capillary size formed in first and second opposite side walls thereof respectively, and enlargements at the upper ends of the slots for facilitating crystal growth, (2) a feed cavity associated with the crucible for receiving solid source material for replenishing the melt, and (3) a passageway between the feed cavity and the crucible for transmitting melted source material to the crucible so as to replenish the melt in the crucible. A plurality of ribbons are formed by positioning a seed between each pair of first and second grooves, contacting the seeds with the melt, and then withdrawing the seeds vertically out of the crucible.

Abstract: An improved apparatus and method is disclosed for use in a system for growing a hollow tubular body of crystalline material by growing the body from the end of a die member, whereby the hollow tubular body can be cut lengthwise along predetermined lines of the body to provide separate crystalline bodies. The apparatus comprises means (preferably in the form of notches provided in the die end of the die member from which the hollow body is grown) for concentrating stress in the hollow tubular body along the predetermined lines as the body is pulled from the die end. The method comprises the steps of (a) growing the tube from a die end of a die member so that stress is concentrated in the tube along predetermined lines as the tube is grown; and (b) cutting the tube along the predetermined lines so as to separate the hollow tube into the plurality of bodies of the crystalline material.

Abstract: An improved optical match to a subsequently-formed antireflection overcoating is achieved by providing a silicon solar cell substrate with an altered surface layer that is formed by an ion-beam process, and has a refractive index between about 3.4 and about 3.6 at 633 nm and between about 3.6 and about 3.8 at 442 nm. The surface layer is formed by adding between about 2% and about 10% methane, by volume, to the hydrogen flow in a Kaufman type broad beam ion source.

Abstract: Apparatus for replenishing a melt while a crystal growing operation is in process. The apparatus comprises an elongated hollow housing member having an open top end and a closed bottom end. A vertically movable support means for supporting a charge of source material, to be added to the melt, is located within the hollow housing member. The apparatus further comprises a conduit means for delivering a predetermined charge of source material to the support means. A charge of source material is delivered to the melt by operation of a retractor means that retracts the support means downwardly within the hollow housing member against the force of a spring means that yieldingly biases the support means upwardly within the hollow housing member towards the open top end of the hollow housing member. When the support means reaches a predetermined release point in its downward motion, the retractor means automatically releases the support means to the force of the spring means.

Abstract: An improvement to the process of passivation of polycrystalline silicon using a broad beam ion source wherein a controlled flow, greater in volume than the background level, of a low molecular weight hydrocarbon vapor is introduced into the vacuum system of the Kaufman-type ion source used for passivation. The amount of hydrocarbon introduced is between about one third of one percent and about ten percent, relative to the hydrogen flow, depending on the hydrocarbon. The process is especially advantageous in producing a passivated layer that functions adequately as a mask for metal plating.

Abstract: An improved apparatus and method is disclosed for use in a system for growing a hollow tubular body of crystalline material by growing the body from the end of a die member, whereby the hollow tubular body can be cut lengthwise along predetermined lines of the body to provide separate crystalline bodies. The apparatus comprises means (preferably in the form of notches provided in the die end of the die member from which the hollow body is grown) for concentrating stress in the hollow tubular body along the predetermined lines as the body is pulled from the die end. The method comprises the steps of (a) growing the tube from a die end of a die member so that stress is concentrated in the tube along predetermined lines as the tube is grown; and (b) cutting the tube along the predetermined lines so as to separate the hollow tube into the plurality of bodies of the crystalline material.

Abstract: A method for electrically interconnecting a plurality of solar cells in series using a multi-faced drum, a first bus spool having an associated first bus strip, and a second bus spool having an associated second bus strip, wherein the method involves placing a solar cell on the then-current top face of the drum so that its top electrode underlies the first bus strip and its bottom electrode overlies the second bus strip, indexing the drum forward one face as the first bus spool is lowered and the second bus spool is raised, placing a new solar cell on the then-current top face of the drum so that its top electrode underlies the second bus strip and its bottom electrode overlies the first bus strip, indexing the drum forward another face as the first bus spool is raised and the second bus spool is lowered, and continuing the foregoing process as desired to interweave the first and second bus strips between additional solar cells.

Abstract: A solar cell fabrication procedure is described which is characterized by (1) forming a front surface mask in the configuration of the front surface electrodes, (2) a passivation step which, inter alia, results in the formation of an altered silicon substrate surface layer in the areas not covered by the front surface mask, (3) removal of the front surface mask, and (4) the use of the altered surface layer as a plating mask for subsequent metallization steps.

Abstract: A solar cell fabrication procedure is described which is characterized by (1) removal of the front surface electrode plating mask after preliminary metallization of the front surface electrodes, (2) a passivation step which, inter alia, results in the formation of an altered silicon substrate surface layer, and (3) use of the altered surface layer as a plating mask for subsequent metallization steps involving, for example, immersion plating of nickel and immersion plating or electroplating of copper.

Abstract: A solar cell fabrication procedure is described in which a hydrogen ion passivation step is used to form, inter alia, an altered silicon substrate surface layer to which immersion plated nickel will not readily adhere. The altered surface layer is formed by shadow casting an ion beam in a pattern corresponding to the desired front surface interelectrode configuration.

Abstract: Apparatus for growing hollow tubular crystalline bodies from the melt includes, in a preferred embodiment, a capillary die of the desired shape, a seed holder having a cross section of similar shape and to which a plurality of elongate seeds may be attached, and an inner after heater of substantially similar shape but smaller size supported from the die by an inner radiation shield.