Mode and device for forming crystal

Abstract

The invention relates to a mode and a device for forming a crystal, which are mainly characterized in that a mode of applying local high cooling to a bottom layer of a crucible is adopted so that the radial extension direction of a liquid phase raw material is formed with most of temperature difference areas to control the formation position and the growing direction of each initially formed nucleus so that each initially formed nucleus grows upwards to form a complete polycrystalline silicon crystal which has the characteristics of high electric inactive crystal boundaries and few number of the crystal boundaries in unit cross-sectional area; particularly, a mode of performing longitudinal cutting along the growing direction of the initially formed nucleus can be further adopted to reduce the crystal boundaries and further increase the photoelectric conversion efficiency of a chip.

Description

technical field [0001] The present invention relates to the improvement of polysilicon crystal forming method and device, aiming to solve the problem that the existing conventional technology cannot enlarge the volume of the initial nucleation or have electrically passive grain boundaries, which leads to chip electrical chips formed by polysilicon crystal slices. The issues of passivity and low photoelectric conversion efficiency. Background technique [0002] Press, solar photovoltaic cell is a kind of semiconductor, so it is also called solar chip, silicon (silicon) is the raw material representative of the current general solar cell, and its power generation principle is to convert sunlight energy into electrical energy. There are many kinds of chip materials for Solar PV Cell, which can be roughly divided into Monocrystalline Silicon (Monocrystalline Silicon), Polycrystalline Silicon (Polycrystalline / Multicrystalline Silicon), Amorphous Silicon (Amorphous Silicon), and o...

AI Technical Summary

Problems solved by technology

[0004] Furthermore, each initial nucleation of the polysilicon crystal is separated by a "grain boundary". The polysilicon crystal formed by the above-mentioned existing technology cannot be enlarged because of the volume of the initial nucleation. image 3 As shown, the conventional polysilicon crystal 10 will have a larger number of initial nucleation 1 per unit area, and the corresponding number of grain boundaries 11 will also be larger, resulting in low photoelectric conversion efficiency of chips formed by slicing the polysilicon crystal 10

[0005] In addition, most of the grain boundaries of polysilicon crystals produced by conventional manufacturing techniques belong to active grain boundaries, and the region where electron holes pass through the active grain boundary will be caught, unable to generate electricity, and become an invalid region; In the passive grain boundary region, electron holes are not affected, and the performance is just like a single crystal

Images