Abstract: A method of manufacturing a solar cell is provided. One surface of a semiconductor substrate is doped with a n-type dopant. The substrate is then subjected to a thermal oxidation process to form an oxide layer on one or both surfaces of the substrate. The thermal process also diffuses the dopant into the substrate, smoothing the concentration profile. The smoothed concentration gradient enables the oxide layer to act as a passivating layer. Anti-reflective coatings may be applied over the oxide layers, and a reflective layer may be applied on the surface opposite the doped surface to complete the solar cell.

Abstract: A simplified manufacturing process and the resultant bifacial solar cell (BSC) are provided, the simplified manufacturing process reducing manufacturing costs. The BSC includes an active region located on the front surface of the substrate, formed for example by a phosphorous diffusion step. After removing the PSG, assuming phosphorous diffusion, and isolating the front junction, dielectric layers are deposited on the front and back surfaces. Contact grids are formed, for example by screen printing. Prior to depositing the back surface dielectric, a metal grid may be applied to the back surface, the back surface contact grid registered to, and alloyed to, the metal grid during contact firing.

Abstract: A simplified manufacturing process and the resultant bifacial solar cell (BSC) are provided, the simplified manufacturing process reducing manufacturing costs. The BSC includes an active region located on the front surface of the substrate, formed for example by a phosphorous diffusion step. The back surface includes a doped region, the doped region having the same conductivity as the substrate but with a higher doping level. Contact grids are formed, for example by screen printing. Front junction isolation is accomplished using a laser scribe.

Abstract: A simplified manufacturing process and the resultant bifacial solar cell (BSC) are provided, the simplified manufacturing process reducing manufacturing costs. The BSC includes a back surface contact grid and an overlaid blanket metal reflector. A doped amorphous silicon layer is interposed between the contact grid and the blanket layer.

Abstract: A method for forming front contacts on a silicon solar cell which includes texture etching the front surface of the solar cell, forming an antireflective layer over the face, diffusing a doping material into the face to form a heavily doped region in valleys formed during the texture-etching of the face, depositing an electrically conductive material on the heavily doped regions in the valleys and annealing the solar cell.

Abstract: Embodiments of the invention generally contemplate methods for treating a semiconductor solar cell substrate to reduce the number of undesirable material defects or interface state traps on the surface or within the substrate. These defects can adversely affect the efficiency of the solar cell because electron-hole pairs tend to recombine with the defects and are essentially lost without generating any useful electrical current. In one aspect, a method of forming a solar cell on a semiconductor substrate is provided, comprising doping a front surface of the substrate, applying a passivating layer to the front surface and/or a back surface of the substrate, and annealing the substrate to reduce the interface state trap density (Dit).

Abstract: Embodiments of the invention contemplate high efficiency emitters in solar cells and novel methods for forming the same. One embodiment of the improved emitter structure, called a high-low type emitter, optimizes the solar cell performance by equally providing low contact resistance to minimize ohmic losses and isolation of the high surface recombination metal-semiconductor interface from the junction to maximize cell voltage. Another embodiment, called an alternating doping type emitter, provides regions of alternating doping type for use with point contacts in the back-contact solar cells. One embodiment of the methods includes depositing and patterning a doped or undoped dielectric layer on a surface of a substrate, implanting a fast-diffusing dopant and/or a slow-diffusing dopant into the substrate either simultaneously or sequentially, and annealing the substrate to drive in the dopants.

Abstract: An apparatus and method for processing substrates are provided. In one embodiment, a susceptor for an apparatus for processing a substrate includes a plurality of segments aligned to form a substrate support surface, each segment having one or more flat surfaces for supporting the substrate, and an opening that extends along an axis of rotation. The susceptor also includes a plurality of rotatable shafts, each shaft positioned in the opening of one of the segments. The method of processing a batch of substrates includes transferring at least one substrate in the batch into a processing chamber and onto a susceptor, processing the at least one substrate within the chamber, transferring the at least one substrate out of the processing chamber, and removing debris from the substrate support surface by rotating the segments to dump any debris on the substrate support surface onto a chamber floor where it will remain during further processing.

Abstract: The present invention relates to improved HIT type or polysilicon emitter solar cells. According to certain aspects, the invention includes forming a masking oxide layer on the front and back of the cell and then patterning holes in the masking oxide. A HIT cell structure or polysilicon emitter solar cell structure is then formed over the patterned oxide, creating the cell junction only in the areas where holes have been cut. Benefits of the invention include that it provides a controlled interface for the HIT cell through insertion of a thin tunnel oxide. Moreover, the tunnel oxide prevents epitaxial growth of amorphous silicon, allowing it to remain amorphous for the optimum band structure. Still further, it provides a layer to protect the surface from plasma damage during deposition of the a-Si layer. Further, it may be used in conjunction with a point contact structure to further increase efficiency.

Abstract: In general, the present invention relates to forming electrical contacts in a semiconductor device, including contact regions in solar cells. According to certain aspects, the invention provides methods and apparatuses for forming plated contacts in the presence of a thin tunnel oxide. Preferably, the tunnel oxide dielectric layer is thin enough to sustain a tunnel current. Plating over the tunnel dielectric is then performed. The benefits of the invention include that no annealing is required to form the metal-silicide contact. Moreover, there is no requirement for special metals for n- or p-type contacts. Another advantage is that shallow contacts according to the invention avoid punching through a shallow junction, thereby enabling the use of shallower emitters with improved blue response. Still further, there is no need to control the amount of silicide metal plated in order to prevent driving the silicide alloy through the junction.

Abstract: The present invention relates to methods and apparatuses for providing a buried insulator isolation for solar cell contacts. According to certain aspects, the invention places a buried oxide under the emitter of a polysilicon emitter solar cell. The oxide provides an excellent passivation layer over most of the surface. Holes in the oxide provide contact areas, increasing the current density to enhance efficiency. The oxide isolates the contacts from the substrate, achieving the advantage of a selective emitter structure without requiring deep diffusions. The oxide further enables use of screen printing on advanced shallow emitter cells. Positioning of the grid lines close to the openings also enables use of a very thin emitter to maximize blue response.

Abstract: The present invention relates to electrical contacts in a semiconductor device, and more particularly to methods and apparatuses for providing point contacts in a polysilicon emitter or HIT type solar cell. According to certain aspects, the invention uses a dielectric layer interposed between the substrate and a conductive layer to provide a limited area over which junction current can flow. The benefit is that the metal grid conductors do not need to align to the contacts, and can be applied freely without registration. Another benefit of the invention is that it provides increased efficiency for poly emitter and HIT cells through use of point contacts to increase current density. A further benefit is that patterning can be accomplished using low cost methods such as inclusion masking, screen printing or laser ablation. A still further benefit is that final contacts do not need alignment to the point contacts, eliminating registration required for conventional point contact designs.

Abstract: The present invention provides a method of forming interconnects in a photovoltaic module. According to one aspect, a method according to the invention includes processing steps that are similar to those performed in conventional integrated circuit fabrication. For example, the method can include masks and etches to form isolation grooves between cells, and additional etches to form a conductive step adjacent to the grooves that can be used to form interconnects between cells. According to another aspect the method for forming the conductive step can be self-aligned, such as by positioning a mirror above the module and exposing photoresist from underneath the substrate at an angle one or more times, and etching to expose the conductive step. According to another aspect, the process can include steps to form grid lines in the module to improve current transport in the structure.

Abstract: A method for forming front contacts on a silicon solar cell which includes texture etching the front surface of the solar cell, forming an antireflective layer over the face, diffusing a doping material into the face to form a heavily doped region in valleys formed during the texture-etching of the face, depositing an electrically conductive material on the heavily doped regions in the valleys and annealing the solar cell.

Abstract: A method of manufacturing a solar cell is provided. One surface of a semiconductor substrate is doped with a n-type dopant. The substrate is then subjected to a thermal oxidation process to form an oxide layer on one or both surfaces of the substrate. The thermal process also diffuses the dopant into the substrate, smoothing the concentration profile. The smoothed concentration gradient enables the oxide layer to act as a passivating layer. Anti-reflective coatings may be applied over the oxide layers, and a reflective layer may be applied on the surface opposite the doped surface to complete the solar cell.

Abstract: Processing steps that are useful for forming interconnects in a photovoltaic module are described herein. According to one aspect, a method according to the invention includes processing steps that are similar to those performed in conventional integrated circuit fabrication. For example, the method can include etches to form a conductive step adjacent to the grooves that can be used to form interconnects between cells. According to another aspect the method for forming the conductive step can be self-aligned, such as by positioning a mirror above the module and exposing photoresist from underneath the substrate at an angle one or more times, and etching to expose the conductive step.

Abstract: A method for forming a selective emitter on a silicon solar cell is provided including forming an oxide layer on a surface of the P-type silicon substrate, implanting phosphorus doping atoms into the oxide layer on the substrate using plasma immersion ion implantation, patterning the oxide layer, annealing the substrate to provide heavily doped regions in the patterned regions and a lightly doped region between the patterned regions, and providing metal contacts to the heavily doped regions.

Abstract: The present invention relates to organic light emitting devices (OLEDs), and more specifically to phosphorescent organic materials used in such devices. More specifically, the present invention relates to emissive phosphorescent material which comprise at least one tridentate ligand bound to a metal center, wherein at least one of the bonds to the tridentate ligand is a carbon-metal bond.

Abstract: The present invention generally comprises a solar cell and a solar cell fabrication process. Photogenerated electrons and electron-holes may have a short lifetime or low mobility that permits the electrons or electron-holes to recombine before reaching the junction. A percolating solar cell device may shorten the distance that the electrons and electron-holes need to travel to reach the junction. The percolating solar cell may be formed by depositing a silicon containing layer with poragens and then decomposing the poragens to create openings such as pores in the silicon containing layer. In one embodiment, the silicon containing layer is deposited and then etched anodically to create openings in the silicon containing layer. The layer deposited over the silicon containing layer may extend into the openings. By extending into the openings, the distance to the junction for electrons and electron-holes may be reduced and more electrons and electron-holes may reach the junction.

Abstract: A method for fabricating point contacts to the rear surface of a silicon solar cell by coating the rear surface with a masking layer and a laser absorptive layer and directing laser radiation to the rear surface to form openings therein after which doping material is applied through the openings and contacts are applied. The doping is preferably performed by plasma immersion ion implantation.