N-doped crystalline silicon and preparation method thereof

Abstract

The invention discloses a preparation method of an N-doped polysilicon ingot. The preparation method comprises the following steps of: putting polysilicon and silicon nitride nanopowder with the grain size of 1 to 100nm in a quartz crucible and charging, vacuumizing a furnace room and heating to 1420 to 1550 DEG C, and preserving the temperature till mixture is fused completely; gradually reducing the cooling speed in 1 to 10 DEG C / min in a furnace till reaching 1350 to 1420 DEG C; then naturally cooling the temperature in the furnace room to the room temperature; taking the silicon ingot outand crushing into small pieces to obtain master alloy silicon blocks; putting mixture of the master alloy silicon blocks, the polysilicon material and electrical activity dopants in the quartz crucible, vacuumizing the furnace room and heating to 1420 to 1550 DEG C to obtain a fused silicon material mixture; and enabling the fused silicon material mixture to solidify to obtain the polysilicon ingot. According to the preparation method of the N-doped polysilicon, the invention can carry out N-doping by adopting conventional devices and has even N-doping, high N-doping concentration, simple entire process and low cost. In addition, the invention also discloses a preparation method of an N-doped monocrystalline silicon ingot.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to single crystal silicon, polycrystalline silicon and a preparation method thereof with relatively high mechanical strength. Background technique [0002] Solar energy is a renewable green energy source. Using the photoelectric conversion properties of semiconductor materials to prepare solar cells can convert solar energy into electrical energy. Since the birth of the first monocrystalline silicon solar cell in 1954, solar cell technology and industry have developed tremendously. Solar cells can be divided into: 1) silicon solar cells; 2) batteries made of inorganic salts such as gallium arsenide III-V compounds, cadmium sulfide, copper indium selenide and other multi-component compounds; 3) solar cells made of functional polymer materials energy batteries; 4) nanocrystalline solar cells, etc. Among them, silicon solar cells, especially crystalline silicon solar cells...

AI Technical Summary

Problems solved by technology

However, under the nitrogen atmosphere of more than 60 hours from melting silicon until the final single crystal is formed, the segregation of silicon nitride is unavoidable, and the precipitation of silicon nitride will inevitably lead to the formation of a large number of dislocations and grain boundaries, thus Growth of monocrystalline silicon cannot be guaranteed

Therefore, if nitrogen doping is carried out through nitrogen, the final nitrogen doping concentration will be limited, and the growth process of single crystal will be limited at the same time.