Method for preparing n-type single crystal silicon and single crystal furnace

Abstract

The invention discloses a method for preparing n-type single crystal silicon and a single crystal furnace, wherein the method for preparing the n-type single crystal silicon comprises the following steps: melting a polycrystalline silicon raw material and an n-type dopant to obtain molten silicon; introducing a seed crystal and straightening to enable crystals to grow out of the molten silicon, and subjecting the crystals to necking and shouldering so as to enter an equal diameter growth stage; and introducing a p-type dopant in at least one period of the equal diameter growth stage to obtainthe n-type single crystal silicon. By adopting the method, the crystal resistivity can be effectively changed, and the usable length can be increased for compliance, so that the problems that the light-doped n-type single crystal silicon having the resistivity greater than 50 ohm.cm is too short in usable length and too poor in yield can be effectively solved.

Description

technical field [0001] The invention relates to the field of single crystal silicon, in particular, the invention relates to a method and a single crystal furnace for preparing n-type single crystal silicon. Background technique [0002] The dopant present in the molten soup will precipitate from the solid-liquid interface into the solid phase (that is, the ingot) during the crystal growth process. Since the solubility of impurities in the solid phase may be different from that in the liquid phase, the concentration of the dopant precipitated out of the solid phase is not equal to the concentration in the liquid phase. This phase is called segregation. The ratio of solid impurity concentration to liquid impurity concentration is called the segregation coefficient. [0003] Generally, the dopant of lightly doped n-type single crystal silicon is phosphorus, and the segregation coefficient of phosphorus is 0.35. The resistivity range of the equal diameter length of the drawn w...

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Problems solved by technology

For this reason, an object of the present invention is to propose a method for preparing n-type single crystal silicon, which can effectively change the crystal resistivity, increase the available length of compliance, and then effectively solve the problem of light doping with a resistivity greater than 50ohm·cm. The available length of n-type monocrystalline silicon is too short and the yield is too poor

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