TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Method: Alternatively, forming contact structure on a solar cell having a p-n junction formed between a first semiconductor region of a first dopant polarity and a second semiconductor region of a second dopant polarity opposite to the first dopant polarity, involves forming a first contact points on a surface of the solar cell, where the contact points provide an electrical connection to the first semiconductor region and are either exposed silicon surfaces or silicon surfaces over which metal pads having a thickness of less than 5 microns are formed; and locating a first conducting wires over the solar cell, where each of the conducting wires makes electrical connection to at least one of the first contact points. Specifically, interconnecting array of solar cells involves forming a contact structure on each solar cell in the array, each solar cell having a p-n junction formed between a first semiconductor region of a first dopant polarity and a second semiconductor region of a second dopant polarity opposite to the first dopant polarity, including: (i) forming a first contact points in one or more spaced parallel linear arrays on a surface of each solar cell, where the contact points provide an electrical connection to the first semiconductor region and are either exposed silicon surfaces or silicon surfaces over which metal pads are formed having a thickness of less than 5 microns; and (ii) forming a second contact points in one or more spaced linear arrays parallel to the spaced linear arrays of first contact points on the same surface of each solar cell as the first contact points, where the second contact points provide an electrical connection to the second semiconductor region and are either exposed silicon surfaces or silicon surfaces over which metal pads having a thickness of less than 5 microns are formed, locating the solar cells in a linear array of solar cells, the spaced linear arrays of first contact points of one solar cell of the array each aligned with respective spaced linear arrays of second contact points of solar cells adjacent to the one solar cell; locating a first conducting wires to extend over the array of solar cells, where each of the first conducting wires is located to pass over the first contact points of one of the spaced linear arrays of first contact points of the one solar cell to make electrical connection to at least one of the first contact points of the one solar cell and every alternate solar cell in the array relative to the one solar cell; locating a second conducting wires to extend over the array of solar cells, where each of the second conducting wires is located to pass over the second contact points of one of the spaced linear arrays of second contact points of the one solar cell to make electrical connection to one or more of the second contact points of the respective spaced linear array of second contact points of the one solar cell and every alternate solar cell in the array relative to the one solar cell; and the first conducting wires of the one solar cell comprise the second conducting wires of the solar cells adjacent to the one solar cell and every alternate solar cell in the array relative to the adjacent solar cells and the second wires of the one solar cell comprise the first conducting wires of the adjacent solar cells and every alternate solar cell in the array relative to the adjacent solar cells. Forming contact structure on solar cell further involves: (a) forming each of the plated metal pads by plating only of a layer of the low-melting temperature metal with a melting point below 150 degrees C onto the exposed first semiconductor regions; (b) forming each of the plated metal pads by plating a layer or layers of nickel, silver and/or tin and plating a layer of the low-melting temperature metal with a melting point below 150 degrees C over the layer or layers of nickel, silver and/or tin; (c) heating the plated metal pads to reflow the low-melting temperature metal layer over edges of the layers of nickel, silver and/or tin; (d) heating the plated metal pads to a temperature 20 degrees C to 50 degrees C higher than the melting temperature of the low-melting point metal to reflow the low-melting temperature metal; (e) fluxing the plated metal pads to remove a native metal oxide prior to reflowing the low-melting temperature metal; (f) selecting the low- melting temperature metal with a melting point below 150 degrees C from alloys of tin with indium and/or bismuth; (g) selecting the alloy from eutectic compositions of tin with indium and/or bismuth; (h) forming the first semiconductor region with a sheet resistance of 80 to 200 ohms/square; (i) forming the first semiconductor region as an n-type region and using light induced plating to plate the metal pads; (j) forming the first semiconductor region as a p-type region and using field induced plating to plate the metal pads; (k) plating the metal pads to a thickness of less than 5 microns; (l) plating the metal pads to a thickness of less than 2 microns; (m) plating the metal pads to a thickness of less than 1 micron; (n) plating the metal pads to a thickness of less than 0.5 micron; (o) forming the first contact points as regions which are circular, oval, square, rectangular or polygonal in shape; (p) forming the first contact points with dimensions in the plane of the surface of the solar cell in the range of 8-12 microns; (q) forming the first contact points as elongate parallel sided regions; (r) forming the elongate parallel sided regions with a width in the range of 8-12 microns; (s) forming the heavily doped regions as elongate parallel channels; or (t) forming the elongate parallel channels with a width of 8-12 micron in the plane of the surface of the solar cell. Forming the first contact points comprises plating the metal pads directly onto exposed surfaces of the first semiconductor region. It also comprises forming a heavily doped regions extending from the exposed semiconductor surface of the solar cell into the first semiconductor region, the heavily doped regions being more heavily doped with dopant of the first dopant polarity than the first semiconductor region and the metal pads are plated onto an exposed surface of the heavily doped region. The method further involves: (a) forming the heavily doped regions with a sheet resistance of 1 to 50 ohms/square; (b) forming a dielectric layer over the first semiconductor region and forming openings in the dielectric layer to expose areas where the heavily doped regions are to be formed, and the metal pads are plated over the heavily doped regions and are electrically connected to the heavily doped regions but are isolated from the remainder of the first semiconductor region by the dielectric layer; (c) forming the heavily doped regions by providing a dopant source on or near the surface of the solar cell and laser heating the dopant source and the first semiconductor region in a pattern corresponding to the locations of the heavily doped regions to cause dopants from the dopant source to dope the heavily doped regions to the required concentration, while simultaneously disrupting the dielectric layer forming openings in the dielectric layer to expose surfaces of the resultant heavily doped regions; (d) locating first wires over the surface of the solar cell to make electrical connection with the first semiconductor region via the metal pads; (e) bonding an encapsulant layer over a surface of the solar cell and the first wires; (f) placing the first wires on the surface of the solar cell before encapsulating the solar cell; (g) attaching the first wires to a sheet of encapsulant and applying the wires to the surface of the solar cell together with the encapsulant; (h) forming the first wires onto the sheet of encapsulant; or (i) forming the first wires by printing a metal seed layer onto the sheet of encapsulant and plating metal onto the metal seed layer to create a wire of a required cross-sectional area. The seed layer is nickel, silver or poly (3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) and the plated metal is copper or silver. The method also involves: (a) plating the conducting first wires with a low-melting temperature metal; (b) selecting the metal of the metal coating plated onto the conducting first wires from alloys of tin with indium and/or bismuth; or (c) selecting the alloy from eutectic compositions of tin with indium and/or bismuth. Forming the first contact points comprises forming metal pads having with a thickness of less than 2 microns on the silicon surface; forming the first contact points comprises forming metal pads having with a thickness of less than 1 micron on the silicon surface; forming the first contact points comprises forming metal pads having with a thickness of less than 0.5 micron on the silicon surface; or forming the first contact points comprises forming a heavily doped regions extending from the surface of the solar cell into the first semiconductor region, the heavily doped regions being more heavily doped with dopant of the first dopant polarity than the first semiconductor region. Forming the heavily doped regions comprises forming regions with a sheet resistance of 1 to 50 ohms/square. Forming the first contact points comprises forming the metal pads directly onto an exposed surface of the first semiconductor region at points where connection between the wires and the first semiconductor region are to be made. The first contact points comprise regions which are circular, oval, square, rectangular or polygonal in shape. The first contact points have dimensions in the plane of the surface of the solar cell in the range of 8-12 microns. The first contact points comprise elongate parallel sided regions. The elongate parallel sided regions have a width in the range of 8-12 microns. Heavily doped regions comprise elongate parallel channels. The elongate parallel channels are 8-12 micron wide in the plane of the surface of the solar cell. The method further involves: (a) placing the conducting wires to cross the elongate parallel channels; (b) placing the conducting wires to cross the elongate parallel channels generally perpendicularly; (c) forming a dielectric layer over the first semiconductor region and forming openings in the dielectric layer to expose areas where the heavily doped regions are to be formed, and placing the conducting wires over the dielectric layer to form a connection to the heavily doped regions through the openings in the dielectric layer; (d) forming metal pads over the heavily doped regions to electrically connect to the heavily doped regions while being isolated from the remainder of the first semiconductor region by the dielectric layer and positioning the wires over the surface of the solar cell to make contact with the first semiconductor region via the metal pads and heavily doped regions; (e) forming the metal pads by plating onto the heavily doped regions; (f) forming the heavily doped regions by providing a dopant source on or near the surface of the solar cell and laser heating the dopant source and the first semiconductor region in a pattern corresponding to the locations of the heavily doped regions to cause dopants from the dopant source to dope the heavily doped regions to the required concentration, while simultaneously disrupting the dielectric layer forming openings in the dielectric layer to expose surfaces of the resultant heavily doped regions; (g) forming a dielectric layer over the first semiconductor region and forming openings in the dielectric layer to expose a surface of the first semiconductor region, and locating the conducting wires over the dielectric layer to connect to the first semiconductor region through the openings in the dielectric layer; (h) forming the metal pads over and electrically connected to the exposed surface of the first semiconductor region such that they are isolated from the remainder of the first semiconductor region by the dielectric layer and locating the wires over the surface of the solar cell in electrical connection with the exposed surface of the first semiconductor region via the metal pads; (i) forming the metal pads by plating metal onto the exposed first semiconductor regions; (j) forming each of the metal pads by plating a layer or layers of nickel, silver and/or tin onto the exposed first semiconductor regions; (k) plating a layer of a metal with a melting point below 150 degrees C over the layer or layers of nickel, silver and/or tin; (l) heating the plated metal pads to reflow the low-melting temperature metal layer over edges of the layers of nickel, silver and/or tin; (m) forming each of the metal pads by plating only a layer of a metal with a melting point below 150 degrees C onto the exposed first semiconductor regions; (n) heating the plated metal pads to a temperature 20 degrees C to 50 degrees C higher than the melting temperature of the low-melting point metal to reflow the low-melting temperature metal; (o) fluxing the plated metal pads to remove a native metal oxide prior to reflowing the low-melting temperature metal; or (p) selecting the metal with a melting point below 150 degrees C from alloys of tin with indium and/or bismuth. The alloy is a eutectic composition of tin with indium and/or bismuth. The method also involves: (a) forming the first semiconductor region with a sheet resistance of 80 to 200 ohms/square; (b) bonding an encapsulant layer over a surface of the solar cell and the wires; (c) placing the wires on the surface of the solar cell before encapsulating the solar cell; (d) attaching the wires to a sheet of encapsulant and applying the wires to the surface of the solar cell together with the encapsulant; (e) forming the wires onto the sheet of encapsulant; (f) forming the wires by printing a metal seed layer onto the sheet of encapsulant and plating metal onto the metal seed layer to create a wire of a required cross-sectional area; (g) selecting the metal seed layer from nickel, silver or poly (3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) and selecting the plated metal from copper or silver; (h) plating the conducting wires with a low-melting temperature metal; (i) heating the plated metal wires to reflow the low-melting temperature metal layer over edges of the layers of copper or silver; (j) heating the plated metal wires to a temperature 20 degrees C to 50 degrees C higher than the melting temperature of the low-melting point metal to reflow the low-melting temperature metal; (k) fluxing the plated metal wires to remove a native metal oxide prior to reflowing the low-melting temperature metal; (l) selecting the metal plated onto the conducting wires from alloys of tin with indium and/or bismuth; or (m) selecting the alloy from eutectic compositions of tin with indium and/or bismuth. The method further involves: (a) forming a second contact points on the same surface of the solar cell as the first contact points, where the second contact points provide an electrical connection to the second semiconductor region and are either exposed silicon surfaces or silicon surfaces over which metal pads having a thickness of less than 5 microns are formed; (b) forming the first contact points in one or more spaced parallel linear arrays and forming the second contact points in one or more spaced linear arrays parallel to the spaced linear arrays of first contact points, the spaced linear arrays of second contact points alternating with the spaced linear arrays of first contact points; (c) locating a second conducting wires over the solar cell, where each of the second conducting wires is located to pass over the second contact points of one of the spaced linear arrays of second contact points and to make electrical connection to one or more of the second contact points of the respective spaced linear array of second contact points; and locating the first conducting wires in locations parallel to the second conducting wires, where each of the first conducting wires is located to pass over the first contact points of one of the spaced linear arrays of first contact points and to make electrical connection to one or more of the first contact points of the respective spaced linear array of first contact points; and (d) locating the solar cell as one solar cell in a linear array of similar solar cells, the spaced linear arrays of first contact points of the one solar cell each aligned with respective spaced linear arrays of second contact points of solar cells adjacent to the one solar cell and the first and second conducting wires of the one solar cell extending across the array of solar cells where the first wires of the one solar cell comprise the second conducting wires of the adjacent solar cells and the second wires of the one solar cell comprise the first conducting wires of the adjacent solar cells. Preferred Assembly: In the solar cell assembly, the first contact points comprise a silicon surface over which the metal pads having a thickness of less than 2 microns are located; the first contact points comprise a silicon surface over which the metal pads having a thickness of less than 1 microns are located; the first contact points comprise a silicon surface over which the metal pads having a thickness of less than 0.5 micron are located; or the first contact points comprise a heavily doped regions extending from the surface of the solar cell into the first semiconductor region, the heavily doped regions being more heavily doped with a dopant of the first dopant polarity than a remainder of the first semiconductor region. The heavily doped regions have a sheet resistance of 1 to 50 ohms/square. The first contact points comprise the metal pads directly contacting an exposed surface of the first semiconductor region at points where connection between the wires and the first semiconductor region are to be made; the first contact points comprise regions which are circular, oval, square, rectangular or polygonal in shape; the first contact points have dimension in the plane of the surface of the solar cell in the range of 8-12 microns; or the first contact points comprise elongate parallel sided regions. The conducting wires are located to cross the elongate parallel channels; or the conducting wires are located to cross the elongate parallel channels generally perpendicularly. A dielectric layer is located over the first semiconductor region and openings in the dielectric layer are located over the heavily doped regions, the metal pads are located in the openings in the dielectric layer and in electrical connection with the heavily doped region and the conducting wires are located over the dielectric layer and connect to first semiconductor region via the metal pads and the heavily doped regions. The metal pads are located over the heavily doped regions and are electrically connected to the heavily doped regions but are isolated from the remainder of the first semiconductor region by the dielectric layer and the wires located over the surface of the solar cell make contact with the heavily doped regions via the metal pads. Dielectric layer is located over the first semiconductor region and openings in the dielectric layer expose a surface of the first semiconductor region, and the conducting wires are located over the dielectric layer and are in electrical connection with the first semiconductor region through the openings in the dielectric layer. The metal pads are located over and electrically connected to the exposed surface of the first semiconductor regions but are isolated from the remainder of the first semiconductor region by the dielectric layer and the wires located over the surface of the solar cell make electrical connection with the first semiconductor region via the metal pads. Each of the metal pads comprises a layer or layers of nickel, silver and/or tin. A layer of a metal with a melting point below 150 degrees C is located over the layer or layers of nickel, silver and/or tin. The metal pads comprise a layer of a metal with a melting point below 150 degrees C. The metal with a melting point below 150 degrees C is selected as an alloy of tin with indium and/or bismuth. Metal of the metal pad is an alloy of tin with indium and/or bismuth. The first semiconductor region has a sheet resistance of 80 to 200 ohms/square. An encapsulant layer is bonded to a surface of the solar cell and extends over the wires. The wires comprise copper or silver. The conducting wires are coated with a metal having a melting point below 150 degrees C. The metal of the metal coating on the conducting wires is selected as an alloy of tin with indium and/or bismuth. The metal pads have a thickness of less than 5 microns; the metal pads have a thickness of less than 2 microns; the metal pads have a thickness of less than 1 micron; or the metal pads have a thickness of less than 0.5 micron. The metal pads located directly on a surface of the first semiconductor region at points where connection between the wires and the first semiconductor region are to be made. The first contact points comprise regions which are circular, oval, square, rectangular or polygonal in shape. The first contact points have dimension in the plane of the surface of the solar cell in the range of 8-12 microns. First contact points comprise elongate parallel regions. The elongate parallel regions have a width in the range of 8-12 microns. The metal with a melting point below 150 degrees C is plated over the layer or layers of nickel, silver and/or tin; the metal pads consist only of a layer of the metal with a melting point below 150 degrees C; or the metal with a melting point below 150 degrees C is selected as an alloy of tin with indium and/or bismuth. The first semiconductor region has a sheet resistance of 80 to 200 ohms/square. Encapsulant layer is bonded to a surface of the solar cell and extends over the wires. The conducting wires are coated with a metal having a melting point below 150 degrees C. The metal of the metal coating on the conducting wires is selected as an alloy of tin with indium and/or bismuth. Second contact points are located on the same surface of the solar cell assembly as the first contact points, where the second contact points provide an electrical connection to the second semiconductor region and are either exposed silicon surfaces or silicon surfaces over which metal pads having a thickness of less than 5 microns are located. The solar cell is located as one solar cell in a linear array of similar solar cells, where the spaced linear arrays of first contact points of the one solar cell are each aligned with respective spaced linear arrays of second contact points of solar cells adjacent to the one solar cell and the first and second conducting wires of the one solar cell extend across the array of solar cells where the first wires of the one solar cell comprise the second conducting wires of the adjacent solar cells and the second conducting wires of the one solar cell comprise the first conducting wires of the adjacent solar cells.