Abstract: A method is provided for forming an opening in a layer of a selected material. The method comprises, forming a polymer resist layer over said selected material and plasticising areas of the resist where openings are to be formed. The plasticising is performed by depositing a first solution onto the surface of said polymer resist layer, where the first solution is a plasticiser selected to increase permeability of the polymer resist layer to a second solution, in an area which has absorbed the first solution. The second solution is selected to be an etchant or solvent for the selected material. After the resist layer has been selectively plasticised, it is contacted with the second solution, which permeates the polymer resist layer in the area of increased permeability and forms an opening in the selected material.

Abstract: A method of forming contacts on a surface emitter of a silicon solar cell is provided. In the method an n-type diffusion of a surface is performed to form a doped emitter surface layer that has a sheet resistance of 10-40 ?/?. The emitter surface layer is then etched back to increase the sheet resistance of the emitter surface layer. Finally the surface is selectively plated. A method of fabrication of a silicon solar cell includes performing a front surface emitter diffusion of n-type dopant and then performing a dielectric deposition on the front surface by PECVD. The dielectric deposition comprises: a. growth of a thin silicon oxide; b. PECVD deposition of silicon nitride to achieve a silicon nitride. The silicon is then annealed to drive hydrogen from the silicon nitride layer into the silicon to passivate the silicon.

Abstract: A method of photoplating a metal contact onto a surface of a cathode of a photovoltaic device is provided using light induced plating technique. The method comprises: a) immersing the photovoltaic device in a solution of metal ions, where the metal ions are a species which is to be plated onto the surface of the cathode of the photovoltaic device; and b) illuminating the photovoltaic device, using a light source of time varying intensity. This results in nett plating which is faster in a direction normal to the surface of the cathode than in a direction in a plane of the surface of the cathode.

Abstract: Surface processing in which the area to be processed is restricted to a predetermined pattern, can be achieved by: (a) providing a layer of a first reagent over a region of the surface to be processed which at least covers an area of the predetermined pattern; (b) providing one or more further reagents which are further reagents required for the processing of the surface; and (c) applying at least one of the further reagents over the region to be processed according to the predetermined pattern; such that the first reagent acts with the one or more of the further reagents to process the surface only in the area of the predetermined pattern. The process is particularly applicable to etching where an etchant having two or more components is used. In that case at least a first etchant component is applied over the surface and at least one further etchant component is applied in the predetermined pattern.

Abstract: A method of selective delivery of material to locations on a substrate using a continuous stream deposition device to deposit the material at selected locations on the substrate. This is achieved by creating a mask with an opening, locating the mask over the substrate and depositing the material through the opening onto the substrate. When locating the mask, over the substrate, a portion of the substrate is exposed through the opening and when the continuous stream deposition device is moved relative to the substrate and the mask, the continuous stream deposition device follows a path relative to the mask which intersects the opening. While the continuous stream deposition device moves, it discharges a continuous stream comprising the material to be delivered, to deposit the material through the mask at a discrete location on the substrate, at the intersection of the opening and the path of the continuous stream deposition device.

Abstract: A solar cell has a metal contact formed to electrically contact a surface of semiconductor material forming a photo-voltaic junction. The solar cell includes a surface region or regions of heavily doped material and the contact comprises a contact metallisation formed over the heavily doped regions to make contact thereto. Surface keying features are located in the semiconductor material into which the metallisation extends to assist in attachment of the metallisation to the semiconductor material.

Abstract: A surface region of a semiconductor material on a surface of a semiconductor device is doped during its manufacture, by coating the surface region of the semiconductor material with a dielectric material surface layer and locally heating the surface of the semiconductor material in an area to be doped to locally melt the semiconductor material with the melting being performed in the presence of a dopant source. The heating is performed in a controlled manner such that a region of the surface of the semiconductor material in the area to be doped is maintained in a molten state without refreezing for a period of time greater than one microsecond and the dopant from the dopant source is absorbed into the molten semiconductor. The semiconductor device includes a semiconductor material structure in which a junction is formed and may incorporate a multi-layer anti-reflection coating.

Abstract: A solar cell comprises adjacent regions of oppositely doped semiconductor material forming a pn junction substantially parallel to front and rear surfaces of the solar cell. A surface of the semiconductor material has a plurality of depressions, with semiconductor material regions forming internal wall surface regions of the depressions being doped to the polarity of one of the semiconductor regions, with which they are in electrical communication. The wall surface regions of the depressions are isolated from the other oppositely doped semiconductor region and form contact points for a contact structure contacting the surface in which the depressions are formed. A dielectric layer is formed over the surface, the dielectric layer being thinner or non-existent in at least a portion of each depression, such that a screen printed metal contact structure formed over the dielectric layer and extending into the depressions makes contact with the semiconductor material in the depressions after sintering.

Abstract: A method of forming a contact structure and a contact structure so formed is described. The structure contacts an underlying layer of a semiconductor junction, wherein the junction comprises the underlying layer of a semiconductor material and is separated from an overlying layer of semiconductor material by creating an undercut region to shade subsequent metal formation. Various steps are performed using inkjet printing techniques.

Abstract: Surface processing in which the area to be processed is restricted to a predetermined pattern, can be achieved by: (a) providing a layer of a first reagent over a region of the surface to be processed which at least covers an area of the predetermined pattern; (b) providing one or more further reagents which are further reagents required for the processing of the surface; and (c) applying at least one of the further reagents over the region to be processed according to the predetermined pattern; such that the first reagent acts with the one or more of the further reagents to process the surface only in the area of the predetermined pattern. The process is particularly applicable to etching where an etchant having two or more components is used. In that case at least a first etchant component is applied over the surface and at least one further etchant component is applied in the predetermined pattern.

Abstract: A method is provided for forming an opening in a layer of a selected material. The method comprises, forming a polymer resist layer over said selected material and plasticising areas of the resist where openings are to be formed. The plasticising is performed by depositing a first solution onto the surface of said polymer resist layer, where the first solution is a plasticiser selected to increase permeability of the polymer resist layer to a second solution, in an area which has absorbed the first solution. The second solution is selected to be an etchant or solvent for the selected material. After the resist layer has been selectively plasticised, it is contacted with the second solution, which permeates the polymer resist layer in the area of increased permeability and forms an opening in the selected material.

Abstract: A photovoltaic device is provided in which a contact structure is formed having a plurality of heavily doped semi-conductor channels formed on a surface of a region to be contacted. The heavily doped semiconductor channels are of the same dopant polarity as the region to be contacted, and form lateral conduction paths across the surface of the region to be contacted. Contact metallisation comprising conductive fingers are formed over the surface of the region to be contacted, and each conductive finger crosses at least some of the heavily doped channels to make electrical contact therewith. The contact structure is formed by forming a layer of dopant source material over the surface to be contacted, and laser doping heavily doped channels in the surface to be contacted. The contact metallisation is then formed as conductive fingers formed over the surface to be contacted and may be screen printed, metal plated or may be formed as buried contacts.

Abstract: A method of forming a contact structure and a contact structure so formed is described. The structure contacts an underlying layer of a semiconductor junction, wherein the junction comprises the underlying layer of a semiconductor material and is separated from an overlying layer of semiconductor material by creating an undercut region to shade subsequent metal formation. Various steps are performed using inkjet printing techniques.

Abstract: A solar cell comprises adjacent regions of oppositely doped semiconductor material forming a pn junction substantially parallel to front and rear surfaces of the solar cell. A surface of the semiconductor material has a plurality of depressions, with semiconductor material regions forming internal wall surface regions of the depressions being doped to the polarity of one of the semiconductor regions, with which they are in electrical communication. The wall surface regions of the depressions are isolated from the other oppositely doped semiconductor region and form contact points for a contact structure contacting the surface in which the depressions are formed. A dielectric layer is formed over the surface, the dielectric layer being thinner or non-existent in at least a portion of each depression, such that a screen printed metal contact structure formed over the dielectric layer and extending into the depressions makes contact with the semiconductor material in the depressions after sintering.

Abstract: In a method for forming a contact on semiconductor surface, a crystalline silicon surface is first oxidized, following which an aluminium layer is deposited onto the oxide layer. A layer of amorphous silicon is then deposited onto the aluminium layer. The structure is then heated to a temperature below the aluminium/silicon eutectic temperature to locally reduce the oxide layer in regions where the quality/density of the oxide layer is lower. Simultaneously, the amorphous silicon penetrates into the aluminium layer, in which it has a high mobility. With continued heating, the aluminium penetrates completely through the oxide layer in localized regions, exposing the crystalline silicon surface. The exposed silicon surface provides a sight for nucleating epitaxial growth, which occurs rapidly as silicon within the aluminium continuously feeds the solid phase epitaxial growth process.

Abstract: In a method for forming a contact on semiconductor surface, a crystalline silicon surface is first oxidized, following which an aluminium layer is deposited onto the oxide layer. A layer of amorphous silicon is then deposited onto the aluminium layer. The structure is then heated to a temperature below the aluminium/silicon eutectic temperature to locally reduce the oxide layer in regions where the quality/density of the oxide layer is lower. Simultaneously, the amorphous silicon penetrates into the aluminium layer, in which it has a high mobility. With continued heating, the aluminium penetrates completely through the oxide layer in localized regions, exposing the crystalline silicon surface. The exposed silicon surface provides a sight for nucleating epitaxial growth, which occurs rapidly as silicon within the aluminium continuously feeds the solid phase epitaxial growth process.

Abstract: A thin film photovoltaic devices is described, having a glass substrate 11 over which is formed a thin film silicon device having an n++ layer 12, a p layer 13 and a dielectric layer 14 (typically silicon oxide or silicon nitride). To create a connection through the p layer 13 to the underlying n++ layer 12, a column of semi-conductor material is heated, the column passing through the various doped layers and the material in the column being heated or melted to allow migration of dopant between layer of the device in the region of the column.

Abstract: A thin film silicon solar cell is provided on a glass substrate, the glass having a textured surface, including larger scale surface features and smaller scale surface features. Over the surface is deposited a thin barrier layer which also serves as an anti-reflection coating. The barrier layer may be a silicon nitride layer for example and will be 70 nm±20% in order to best achieve its anti-reflection function. Over the barrier layer is formed an essentially conformal silicon film having a thickness which is less than the dimensions of the larger scale features of the glass surface and of a similar dimension to the smaller scale features of the glass surface.

Abstract: A method of making contacts on solar cells is disclosed. The front surface (41) of a substrate (11) is coated with a dielectric or surface masking layer or layers (12) that contains dopants of the opposite polarity to those used in the surface of the substrate material (11). The dielectric layers or layers (12) not only acts as a diffusion source for forming the emitter for the underlying substrate (11) when heat treated, but also acts as a metallization mask during the subsequent electroless plating with solutions such as nickel and copper. The mask may be formed by laser scribing (14) which melts the layer or layers (12), thereby more heavily doping and exposing zones (15) where metallization is required.

Abstract: The method is provided for contact formation in semiconductor devices. The method involves forming an insulating layer over an active region to be contacted to, forming holes or openings in the insulating layer to expose the active region and forming an aluminium layer over the insulating layer. A source of non-crystalline semiconductor material or damaged crystalline material is located in contact with the aluminium layer such that the non-crystalline or damaged crystalline material is dissolved in the aluminium layer and redeposited on the surface of the semiconductor material to be contacted to. The semiconductor material is deposited by solid phase epitaxial growth and carries with it, aluminium atoms which leave the semiconductor material as heavily doped p-type material.