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Method for producing solar cells having selective emitter

A solar cell and emitter technology, applied in the field of solar cells, can solve the problems of high emitter saturation current, layer resistance non-uniformity, high dopant surface concentration, etc.

Inactive Publication Date: 2012-05-09
SOLARWORLD IND THURINGEN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, the unevenness of the temperature and concentration of the etching medium or decomposed products in the etching pool leads to the unevenness of the layer resistance, which adversely affects the efficiency of the cell.
The etch solution required there is extremely corrosive, which makes it difficult to select a suitable masking lacquer
In addition, the emitter profiles produced after backside etching always still have too high a dopant surface concentration, which results in undesirably high emitter saturation currents

Method used

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  • Method for producing solar cells having selective emitter
  • Method for producing solar cells having selective emitter

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Embodiment Construction

[0035] In the method according to an embodiment for the production of selective emitters with special properties by additionally inserting structured sources, the wafer etched away from cutting damage and possible texturing is first applied and slightly inwardly diffused with doping sources such as phosphosilicate glass (PSG) ( figure 1 a). In this case, the silicon wafer is assigned the reference number 1 and the diffusion source applied over the entire surface is assigned the reference number 2 . The region of slight inward diffusion is indicated by reference numeral 5 .

[0036] For example, in this step, generate 100 to 200 layer resistance between them. This can be achieved by gas phase diffusion (e.g. phosphorus oxychloride (POCl 3 )) in a combined process step with temperature treatment, for example in a quartz tube furnace.

[0037] It is also possible to generate a dopant source, such as PSG, by means of Atmospheric Plasma Chemical Vapor Deposition (APCVD) and ...

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Abstract

The invention relates to a method for producing solar cells having a selective emitter. Wafers (1) having no saw damage are first provided. A full-surface application of a doping source (2) to the wafer and a light, first inward diffusion of the dopant are then carried out until a first film resistor region is obtained. The applied doping source is then structured, wherein only those regions (4) remain as a result of the structuring that substantially correspond to the sections on the wafer to be contacted later. Another, second diffusion from the remaining regions of the doping source into the wafer volume is then carried out until a second film resistor region for the selective emitter (4) and a simultaneous redistribution of the dopant (5) introduced during the first diffusion are obtained, having the goal of lowering the dopant concentration in the region near the surface that is no longer covered by the doping source, under the condition that the film resistor values of the first film resistor region are larger than those of the second film resistor region.

Description

technical field [0001] The invention relates to a method for producing a solar cell with a selective emitter. Background technique [0002] Solar cells are currently produced industrially by the so-called fire-through-SiNx (Firing-Through-SiNx) method. Here, the diffusion of phosphorous on the front side of the cell generates 40 to 80 Uniform emitter with layer resistance or sheet resistance in the range. A further layer of silicon nitride is deposited on this layer, which serves for passivation and reflection reduction. Next, a contact grid consisting of silver paste is applied. In the sintering step, the aforementioned paste is baked. Special components in the silver paste make it possible to form an electrical contact between the contact grid and the actual emitter. A disadvantage of this type of contact configuration is that a very high doping of the emitter is necessary in order to achieve a sufficiently low contact resistance. This in turn leads to high losses i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L21/225H01L31/18H01L31/068
CPCH01L31/1804H01L21/2255H01L31/068Y02E10/50Y02E10/547Y02P70/50
Inventor T. 维特里希J. 洛森M. 魏斯K. 迈耶
Owner SOLARWORLD IND THURINGEN