N-doped crystalline silicon and preparation method thereof

Abstract

The invention discloses a preparation method of an N-doped polysilicon ingot, which comprises the following steps that: the mixture of polysilicon material, silicon nitride nano powder with the grain size of 1 to 100nm and electrically active dopant is put into a quartz crucible and is loaded into a furnace; a furnace chamber is vacuumized and heated to 1420 to 1550DEG C, the temperature is insulated until the mixture is fully melted, to obtain molten silicon mixture; and then the molten silicon mixture is solidified to obtain the polysilicon ingot, wherein the electrically active dopant is any one type of B, P or Ga and the added amount makes the concentration of the electrically active dopant in the polysilicon ingot be 0.02 to 2ppm, and the added amount of the silicon nitride nano powder makes the nitrogen concentration in the polysilicon ingot be 0.0002 to 1ppm. The preparation method of N-doped polysilicon can dope nitrogen with existing equipment, and has the advantages of uniform nitrogen doping, high concentration of doped nitrogen, simple and easily controllable process and low cost. In addition, the invention also discloses a preparation method of an N-doped mono-crystalline 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 is doped through nitrogen, the final nitrogen doping concentration will be limited, and the growth process of single crystal will be limited.