Method and device for casting crystal material by using crystal selector

Abstract

The invention generally relates to a vertical directional solidification casting method using a crystal selection process, which is used for manufacturing a crystal material with a reserved crystal orientation and comprises a polycrystal material and a monocrystal material. When a traditional method for casting the crystal by using the crystal selection process is used for producing the crystal with a bigger size, the problems that the crystal selection effect is bad, a mixed crystal is easy to generate, the internal stress is high, the monocrystal material is hard to obtain or the expected quality requirement is hard to reach and the like exist. The problems are solved by the invention through providing a gradually-changed crystal growth area of which the horizontal cross section is gradually increased, thereby, a good crystal growth effect is obtained, and the obtained cast monocrystal or polycrystal material, such as silicon or silicon germanium, has fewer defects, high quality and a good performance, and is especially suitable for the application of the semiconductor field and the photovoltaic field.

Description

technical field [0001] The present invention generally relates to the use of vertical solidification casting methods, such as vertical temperature gradient solidification crystal growth method (hereinafter also referred to as VGF method) or vertical Bridgman crystal growth method (hereinafter also referred to as VB method) or vertical Bridgman method. The Stockbag method (VBS method) produces relatively large silicon and silicon germanium crystalline materials, especially polycrystalline and single crystal materials suitable for photovoltaic applications. Background technique [0002] Photovoltaic cells (or photovoltaic cells, solar cells) based on crystalline silicon should have the greatest possible efficiency of converting solar radiation power into electric current, as well as the longest possible service life and decay rate. This is determined by a variety of factors, such as the purity of silicon raw materials, the type of silicon crystal (single crystal, polycrystalli...

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Problems solved by technology

The specific method is to use the seed crystal induction method. In the VGF, VB or BVS method, a silicon single crystal seed crystal is placed at the bottom of the silicon melt to induce crystal growth. However, many attempts have failed, and none of the crystals obtained polysilicon

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