Method for the manufacture of solar cells

A technology of solar cells and wafers, applied in circuits, photovoltaic power generation, electrical components, etc., can solve problems such as wafer cracks

Inactive Publication Date: 2016-07-20
SOLVAY FLUOR GMBH DE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

These wafers may have cracks from the cutting process

Method used

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  • Method for the manufacture of solar cells

Examples

Experimental program
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Effect test

example

[0060] General: Simple unstructured silicon wafers of 200 mm were etched in a microwave plasma etcher produced by Secon Semiconductor Equipment GmbH in Austria. The wafers were weighed before and after etching, and the difference in weight indicated the etch rate. In the absence of a water-cooled chuck, limit the etching time to a few 10 min intervals of 3 min for cooling. Example 1 and Example 4 are comparative examples.

[0061] 1. Test results

[0062]

[0063] Ar is used to improve the homogeneity of the plasma over the length of the microwave rod. It has no effect on Si etching reaction. Y / N indicates it is turned on or turned off.

[0064] Use the same MFC (mass flow controller) gas flow for SF 6 and COF 2 . The MFC for SF 6 calibration. to COF 2 A conversion factor of 2 (0.544 / 0.27) has been used.

[0065] These experiments show that carbonyl fluoride can be successfully used to etch the surface of silicon wafers, the etching time can be shortened and stil...

example 2

[0066] Example 2: Silicon Wafer Processing to Make Cracks Harmless

[0067]A boron-doped silicon wafer sawn from a polysilicon block had cracks at the edges. The wafer is transferred into a plasma chamber. The chamber was evacuated and carbonyl fluoride was introduced into the chamber to reach a pressure of 0.4 mbar and the plasma was started. During the plasma treatment, the initial sharp-edged crack is transformed into a keyhole-like structure that will not grow; in this way, the wafer is no longer useless, but can be used for further processing to obtain a Solar cells (doping with phosphorus, attaching electrodes, etc.).

example 3

[0068] Example 3: Removal of a P-containing glassy coating

[0069] A silicon wafer doped with boron and POCl 3 Contact and heat between 960°C and 1000°C to convert phosphorus compounds into P 2 o 5 . As a side reaction, a phosphorous-silica glassy coating is formed. To remove the glassy coating, the wafer was positioned in a plasma processing chamber, the chamber was evacuated, and neat carbonyl fluoride was introduced into the reactor until a pressure of 0.4 mbar was reached. Then, start the plasma. Once the glassy coating is etched away, the process is stopped.

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Abstract

The invention relates to a method for the manufacture of solar cells. Solar cells are manufactured from P-type doped monocrystalline or polycrystalline silicon ingots by sawing wafers and applying an N-type doping. The wafers can be improved by etching them, especially in a plasma assisted process, with fluorine, carbonyl fluoride or NF3. Hereby, the surface is roughened so that the degree of light reflexion is reduced, cracks caused from the sawing operation are prevented from proliferation, and glass-like phosphorus-containing oxide coatings caused by phosphorus doping are removed.

Description

[0001] This application is a divisional application of a Chinese patent application with an application date of April 28, 2008, an application number of 200880125466.7, and an invention title of "Method for Producing Solar Cells". [0002] This application claims the benefit of US Provisional Patent Application No. 61 / 022958, filed January 23, 2008, the entire contents of which are incorporated herein by reference. technical field [0003] The invention relates to a method for producing solar cells. In another aspect of the invention, the invention relates to a method for producing a flat panel. Background technique [0004] Solar cells are used to convert sunlight into electricity. They are usually produced from monocrystalline ingots of boron-doped silicon (P-type doped) or from cast silicon ingots (polysilicon, P-type doped with boron) by cutting out wafers of the desired size from the bulk material. in production. Then, a layer of silicon doped with phosphorous is for...

Claims

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Application Information

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IPC IPC(8): H01L31/18
CPCH01L31/18H01L31/188H01L27/1214H01L31/02363H01L31/1804Y02E10/547Y02E10/546Y02P70/50H01L31/02366H01L21/3065H01L31/04
Inventor马尔塞洛·里瓦
OwnerSOLVAY FLUOR GMBH DE