CN101724826A

CN101724826A - Surface treatment method for C-C heating element

Info

Publication number: CN101724826A
Application number: CN201010300132A
Authority: CN
Inventors: 吴学林; 郭建彬; 董先君
Original assignee: YICHANG NANBO SILICON MATERIALS CO Ltd
Current assignee: YICHANG NANBO SILICON MATERIALS CO Ltd
Priority date: 2010-01-08
Filing date: 2010-01-08
Publication date: 2010-06-09
Anticipated expiration: 2030-01-08
Also published as: CN101724826B

Abstract

The invention discloses a surface treatment method for a C-C heating element, and relates to a polysilicon production process. In the surface treatment method, the conventional hydrogenation production equipment and new technological parameters are adopted, a layer of simple substance silicon is generated in holes and surfaces of the C-C heating element, and then a SiC film is generated through high temperature diffusion. The surface treatment method has the advantages that: raw materials hydrogen and silicon tetrachloride have high purity, so new impurities cannot be introduced, the generated SIC has stable performance and good electrical performance, the SiC film is difficult to damage or fall off, resists corrosion and erosion and effectively protects the C-C heating element, the service life of the C-C heating element is prolonged to over 4,500 hours from 2,500 hours, and the C-C heating element has good economic use value and has positive function on polysilicon closed-loop continuous stable production.

Description

A kind of C-C heating element surface-treated method

Technical field

The present invention relates to production of polysilicon technology, the C-C heating element is the vitals in the hydrogenation process of Siemens process polycrystalline silicon loop production, is about to the by product SiCl in the production of polysilicon ₄Be converted into SiHCl ₃, SiHCl wherein ₃It is the important source material of producing polysilicon.Particularly a kind of C-C heating element surface-treated method.

Background technology

The heating element of using in the hydrogenation furnace stove of Russia rare metal research institute design is the C-C heating material, the C-C heating material that Russia company provides is very expensive, the domestic this heating element producer that can provide is also less than 4 families, and they only promise to undertake that the C-C heating material has only 2500 hours work-ing life.And after arriving work-ing life, the heating material that need more renew causes to produce and pause, and expense is higher, causes the production cost height, greatly limits the loop production of polysilicon at every turn.

The C-C heating element of hydrogenation furnace production usefulness is with the accurate three way structure precast body of needled carbon cloth, by high temperature cabonization, purifying, machining, forms by vapor-phase thermal cracking surface deposition one deck carbon dust then.Its manufacture craft itself has determined this heating material to have the internal void defective, though can prolong its life-span by top coat, but fact proved that this coating very easily comes off under the situation of colding and heat succeed each other and corroded by processing medium, the life-span has a greatly reduced quality.

Summary of the invention

Technical problem to be solved by this invention provides a kind of C-C heating element surface-treated method, can generate the SiC film of difficult drop-off on C-C heating element surface by adopting existing hydrogenation production unit, prolongs C-C heating element work-ing life.

For solving the problems of the technologies described above, the technical solution adopted in the present invention is: a kind of C-C heating element surface-treated method, the C-C heating element of packing in hydrogenation furnace is with N ₂The displacement furnace air is given the energising of C-C heating element, catches up with that nitrogen is empty to be burnt, progressively temperature raising to 800 ℃; H ₂Displacement N ₂, be warming up to 1080-1200 ℃ of empty the burning 1 hour; Feed H by mole proportioning 10～20: 1 then ₂With SiCl ₄Gas mixture, the chemical vapour deposition polysilicon stopped gas mixture after 1-1.5 hour, and logical H ₂Be warming up to and kept more than 1250 ℃ 4 hours, High temperature diffusion impels C-C heating element surface to generate the SiC film, obtains the C-C heating element that the surface generates the SiC film.

A kind of C-C heating element surface-treated method provided by the invention; by adopting former hydrogenation production unit; the parameter of adopting new technology; generate one deck elemental silicon at C-C heating element hole and surface; generate the SiC film by High temperature diffusion again; its beneficial effect is: the high-purity characteristics of starting material hydrogen and silicon tetrachloride can not introduced new impurity; the SiC stable performance that generates; good electrical property; the SiC film is survivable or come off; anticorrosive; the anti-impact erosion; effectively protect the C-C heating element; prolong the C-C heating element life-span, work-ing life is from original 2500 hours, extends to present more than 4500 hours; have better economic use value, polysilicon closed loop continuous and stable production is had active effect.

Description of drawings

Fig. 1 is the structural representation of hydrogenation furnace among the present invention.

Embodiment

The present invention impels H by hydrogenation process equipment ₂And SiCl ₄Under suitable temperature; generate fine and close polysilicon on C-C heating material surface, under hydrogen environment, impel the C of polysilicon and C-C heating element to react then by adjusting temperature; generate the SiC protective membrane, to reach the purpose in the life-span that prolongs the C-C heating element.

2H ₂+SiCl ₄→Si+4HCl

Si+C→SiC

In Fig. 1, a kind of C-C heating element surface-treated method, the C-C heating element 3 of packing in the body of heater 2 of hydrogenation furnace enters the mouth 1 with N from process gas ₂Air in the displacement body of heater 2 give the C-C heating element 3 energisings, catch up with that nitrogen is empty to be burnt, progressively temperature raising to 800 ℃; Enter the mouth 1 with H from process gas ₂Displacement N ₂, be warming up to 1080-1200 ℃ of empty the burning 1 hour; Feed H by certain mole proportioning 10～20: 1 then ₂With SiCl ₄Gas mixture, the chemical vapour deposition polysilicon stopped gas mixture after 1-1.5 hour, and logical H ₂Be warming up to and kept more than 1250 ℃ 4 hours, High temperature diffusion impels C-C heating element (3) surface to generate the SiC film, obtains the C-C heating element 3 that the surface generates the SiC film.Reacted gas is discharged from process gas outlet 4.

Extend to more than 4500 hours for 3 work-ing lifes through the C-C heating element after the surface treatment.

Claims

1. C-C heating element surface-treated method is characterized in that may further comprise the steps: the C-C heating element (3) of in hydrogenation furnace, packing into, with N2 displacement furnace air, give C-C heating element (3) energising, and catch up with that nitrogen is empty to be burnt, progressively temperature raising to 800 ℃; H2 replaces N2, is warming up to 1080-1200 ℃ of empty the burning 1 hour; Feed H2 and SiCl4 gas mixture by mole proportioning 10～20: 1 then; the chemical vapour deposition polysilicon; 1-1.5 stop gas mixture after hour; and logical H2 is warming up to and kept more than 1250 ℃ 4 hours; High temperature diffusion; impel C-C heating element (3) surface to generate the SiC film, obtain the C-C heating element that the surface generates the SiC film.