TWI484075B - Method of umg-si production with metallurgy - Google Patents

Description

Method for manufacturing polycrystalline germanium by metallurgical method

The present invention is a method for producing polycrystalline germanium, and more particularly to a method for producing polycrystalline germanium in combination with metallurgy.

There are two main uses for polycrystalline germanium products: one for solar cells and the other for integrated circuits. The performance parameters of polycrystalline germanium products are also different for the two applications. The purity of electronic grade polycrystalline germanium is required to reach 9N~11N. However, under the premise of ensuring photoelectric conversion efficiency and lifetime, the requirements of the purity of polycrystalline germanium are not so high. High, roughly around 6N~7N.

Electronic grade polysilicon is generally a costly chemical process, primarily an improved Siemens process, while solar grade polysilicon can employ some physical methods to reduce production costs. At present, in addition to the improved Siemens method for the preparation of solar grade polycrystalline germanium, there are metallurgical processes, decane processes and fluidized bed processes.

The requirements for the polycrystalline germanium material from Dayang energy level are not so high, and the general purity is 6N-7N. If the purity is higher than 7-9, it is necessary to add an appropriate amount of borophosphorus doping to the polycrystalline germanium to reduce the purity before it can be used for photovoltaic power generation. This is a physical contradiction and increases manufacturing costs. Therefore, there should be a production technology for sputum production using photovoltaics.

The production of solar grade polysilicon by metallurgy is one of the most promising replacement technologies. Metallurgical methods have the advantages of low cost, short construction period and no chemical pollution. However, so far, the domestic preparation of polycrystalline germanium by metallurgy is still in the scientific research, small-scale experiments, and the products still do not meet the quality requirements of solar-grade polycrystalline germanium, and the stability is also poor, and the attenuation is severe during use. Metallurgical polycrystalline germanium products may also have some problems, but one thing that can be affirmed is that metallurgical processes have a series of advantages such as simple process and low energy consumption.

The metallurgical process produces polycrystalline germanium.

Metallurgical methods have the advantages of low cost, short construction period and no chemical pollution. However, so far, the domestic preparation of polycrystalline germanium by metallurgy is still in the scientific research, small-scale experiments, and the products still do not meet the quality requirements of solar grade crucibles, the stability is also poor, the attenuation during use is serious, and if the metallurgical method is In order to achieve mass production, considering the factors of impurities such as boron and phosphorus removal, the equipment required is a large and efficient vacuum equipment, and the RH vacuum furnace is the most suitable. After removing boron and phosphorus, it can be obtained by pickling. A uniform solar grade polycrystalline germanium material characterized by the following steps:

1. Liquid metallurgy crucible, injected into the crucible, and simultaneously remove boron (B) phosphorus removal (P) in the RH vacuum furnace to complete the metallurgical polycrystalline removal B removal process.

2. When B < 0.4 ppm, P < 0.8 ppm, it was cast and solidified.

The present embodiment is a method for manufacturing polycrystalline germanium by metallurgy, which is produced by melting a metallurgical crucible by a submerged arc furnace; and then injecting the metallurgical crucible into a RH-MFB vacuum furnace (Chinese translation: multi-function nozzle vacuum circulation refining furnace) Performing a metallurgical polycrystalline germanium dephosphorization and dephosphorization process until the metallurgical crucible contains less than 0.4 ppm of boron and less than 0.8 ppm of phosphorus; then, the metallurgical crucible of the boron removal and phosphorus removal step is taken out for casting solidification, and then crushed After removing the metal impurities (including iron) by pickling, polycrystalline germanium is formed.

The polycrystalline germanium produced by the above method is directly used as a solar grade polycrystalline germanium, and can be directly cast into an ingot by vacuum directional solidification in a vacuum polycrystalline ingot furnace, and can be used for subsequent slicing processing. Since the polycrystalline silicon obtained by the present embodiment is already in the solar grade and does not need to be processed repeatedly, the time and cost can be saved, and the problems caused by the prior art are overcome.

Hereinafter, the second embodiment will be further enumerated by the same method, so that those skilled in the art can better understand the features of the method.

(1) melting the metallurgical crucible through an intermediate frequency furnace; injecting the metallurgical crucible into the RH-MESID vacuum furnace (Chinese translation: pulsed airflow vacuum cycle refining furnace) to carry out the metallurgical polysilicon dephosphorization and dephosphorization process until the metallurgical crucible contains The boron is less than 0.4 ppm and the phosphorus is less than 0.8 ppm; then, the metallurgical crucible which completes the boron removal and phosphorus removal step is taken out for casting and solidification, and then crushed, and the metal impurities are removed by pickling to form polycrystalline germanium.

(2) Producing metallurgical crucible through a smelting furnace; then injecting the metallurgical crucible into a RH-KTB vacuum furnace (Chinese translation: top-blown oxygen vacuum cycle refining furnace) for metallurgical polycrystalline strontium boron removal and phosphorus removal process until the metallurgy The bismuth contained less than 0.4 ppm of boron and less than 0.8 ppm of phosphorus; then, the metallurgical mash which completes the boron removal and phosphorus removal step is taken out for casting and solidification, and then crushed, and after removing metal impurities by pickling, polycrystalline germanium is formed.

However, the embodiments described in the above description are merely illustrative of the principles of the invention and its effects, and are not intended to limit the invention. Therefore, those skilled in the art can make modifications and changes to the above embodiments without departing from the spirit of the invention. The scope of the invention should be as set forth in the appended claims.

Claims (6)

A method for manufacturing polycrystalline germanium by metallurgy method, which comprises: melting a metallurgical crucible through a submerged arc furnace; and injecting the metallurgical crucible into a RH-MFB vacuum furnace to perform a metallurgical polysilicon dephosphorization and dephosphorization process until the metallurgical crucible comprises The boron is less than 0.4 ppm and the phosphorus is less than 0.8 ppm; then, the metallurgical crucible which completes the boron removal and phosphorus removal step is taken out for casting and solidification, and then crushed, and the metal impurities are removed by pickling to form polycrystalline germanium. A method of producing polycrystalline germanium by a metallurgical process as described in claim 1, wherein the metallic impurity comprises iron. A method for manufacturing polycrystalline germanium by metallurgy method, which comprises: producing metallurgical crucible by melting in an intermediate frequency furnace; injecting the metallurgical crucible into a RH-MESID vacuum furnace to perform a metallurgical polycrystalline germanium dephosphorization and dephosphorization process until the metallurgical crucible comprises The boron is less than 0.4 ppm and the phosphorus is less than 0.8 ppm; then, the metallurgical crucible which completes the boron removal and phosphorus removal step is taken out for casting and solidification, and then crushed, and the metal impurities are removed by pickling to form polycrystalline germanium. A method of producing a polycrystalline germanium by a metallurgical process as described in claim 3, wherein the metallic impurity comprises iron. A method for manufacturing polycrystalline germanium by metallurgy method, which comprises: melting a metallurgical crucible through a submerged arc furnace; and injecting the metallurgical crucible into a RH-KTB vacuum furnace for a metallurgical polysilicon dephosphorization and dephosphorization process until the metallurgical crucible comprises The boron is less than 0.4 ppm and the phosphorus is less than 0.8 ppm; then, the metallurgical crucible which completes the boron removal and phosphorus removal step is taken out for casting and solidification, and then crushed, and the metal impurities are removed by pickling to form polycrystalline germanium. A method of producing a polycrystalline germanium by a metallurgical process as described in claim 5, wherein the metallic impurity comprises iron.