CN101237005A

CN101237005A - Forming method for micro crystal silicon film

Info

Publication number: CN101237005A
Application number: CNA2007100025704A
Authority: CN
Inventors: 李沅民; 马昕
Original assignee: BEIJING XINGZHE MULTIMEDIA TECHNOLOGY Co Ltd
Current assignee: BEIJING XINGZHE MULTIMEDIA TECHNOLOGY Co Ltd
Priority date: 2007-01-29
Filing date: 2007-01-29
Publication date: 2008-08-06

Abstract

The present invention discloses a method for manufacturing a hydrogenated microcrystalline silicon film. Firstly a hydrogenated microcrystalline silicon seeding layer having a crystal nucleus is formed on a substrate, and then a hydrogenated amorphous silicon film with a thickness of no more than 3 micrometers is formed quickly by a plasma chemical vapor deposition method. Afterwards the material is put under high pressure hydrogen circumstance which is no less than 500 atmospheres, and at temperature no more than 300 DEG.C, the duration is 3 to 10 hours, thereby the hydrogenated microcrystalline silicon suitable for photoelectric conversation is obtained.

Description

The formation method of microcrystalline silicon film

Technical field

The invention belongs to semi-conducting material and prepare scope, specially refer to the technology of preparing of thin-film solar cells material.

Background technology

Solar energy power generating is to obtain to help one of important channel of the regenerative resource of environment, and recent years, film photovoltaic cell and large tracts of land photovoltaic module have caused common people's extensive concern all the more.Especially amorphous silicon hydride, nanocrystal silicon and microcrystal silicon, they have demonstrated great potential along with the extensive use of photovoltaic device in commercial and dwelling house facility.Produce thin film silicon photovoltaic device being lower than under 260 ℃ of so low relatively temperature, an outstanding feature is, the semiconductor film of can the large tracts of land deposition relevant function admirable with silicon with electrically contact rete.Simultaneously, can use ripe advanced filming equipment and program and make the lower substrate of production cost.Be applied to laser scribing moulding (laser patterning) technology of the different films on the same substrate, allow a plurality of solar cell devices in film deposition process, directly to form the large tracts of land photovoltaic template of integrated form.

Photovoltaic device also is solar cell or optical-electrical converter, is used for a radiation, changes into electric energy such as sunlight, incandescence or fluorescence etc.This conversion produces by so-called photoelectric effect.When irradiate light arrives photovoltaic device, absorbed by the active regions of device, it is right to form electronics and hole, and these electronics and hole are separated by the built-in electric field of device then.According to the structural analysis of the solar cell of known use amorphous silicon hydride and nanocrystal silicon and microcrystal silicon, internal electric field is to produce in the structure that contains p type, intrinsic (i) type and the n type rete (p-i-n) made by amorphous silicon and/or nanocrystal silicon and microcrystal silicon.In the photovoltaic cell that comprises p-i-n type structure, when light of proper wavelength is absorbed, will generate electron-hole pair in the non-doping type intrinsic i layer of battery.Under the influence of built-in electric field, electronics-hole is separated, and electron stream is to n type conduction region, and the hole flows to another one p type conduction region.Photovoltaic cell has absorbed after the light, and this electronics-hole stream will generate photovoltage.

The semi-conducting material of making photovoltaic device will have the extinction ability, produces a large amount of electronics and hole, and can change into useful electric energy to the luminous energy of incident as much as possible, and then improve transformation efficiency.In this respect, microcrystal silicon with respect to nanocrystal silicon particularly amorphous silicon have advantage because the absorption long-wave radiation that it can be stronger, and have better opto-electronic conversion ability, and do not have problem of unstable under the illumination.Microcrystal silicon is an ideal material of making photovoltaic device, because and the material that uses in other photovoltaic cell, particularly polysilicon is compared, it can be no more than under several microns the thickness, absorb most solar radiation, this is far smaller than the thickness of crystal silicon solar batteries.

Known in the current techniques, in the photovoltaic cell of p-i-n type based thin film silicon, the non-doping type intrinsic i layer between p layer and the n layer is much thicker than p layer and n layer.The effect of intrinsic i layer be stop electronics and hole in built-in electric field separated before combination again.Generally, if radiation is incident on the p layer, this structure is called as " p-i-n " structure; And if be incident on the n layer, be called as " n-i-p " structure.The photovoltaic template of currently marketed all based thin film silicon all is the p-i-n type.

Though microcrystal silicon is very potential thin-film solar cells material, but its present distinct disadvantage is the tediously long complex process of its growth, and must use accurate and expensive plasma deposition apparatus, productivity ratio is very low, can consume a large amount of highly purified sources gas (mainly being hydrogen) simultaneously, particularly when large-area coating film, its uniformity extremely is difficult to ensure, particularly when high speed deposition.The tangible problem of another one be exactly in this material against vacuum chamber impurity very responsive, so must use coating system to deposit p layer, n layer and i layer respectively usually with a plurality of vacuum chambers.As above problem makes the microcrystalline silicon solar cell that directly uses the plasma chemistry gas phase to grow continuously not have competitiveness cheaply.So necessaryly seek a kind of simplyr, reliable, be convenient to the method for the formation microcrystal silicon of industrialization.

Summary of the invention

Based on above-mentioned consideration, the applicant has worked out primary and foremost purpose of the present invention: the method that provides a kind of microcrystalline hydrogenated silicon to form.

The further purpose of the present invention provides a formation method of being convenient to the microcrystalline silicon solar cell of industrialization.

In order to reach the foregoing invention purpose, the present invention proposes a method that is divided into the acquisition high-quality microcrystalline silicon in two steps, the first step method of plasma enhanced chemical vapor deposition, obtain as shown in Figure 1, one that forms on substrate 3 its bottom is the hydrogenation non crystal silicon film 18 of seeding layer 17, and the growth rate of this amorphous silicon membrane is not less than 1 nm/sec, and thickness is no more than 3 microns, make its atomic structure very not compact, and help crystallization process thereafter.Second step was to be not less than in 500 atmospheric hydrogen gas environments at one, not being higher than under 300 ℃ the temperature, this anneal of material was handled 3-10 hour, thereby was obtained being suitable for being used as the microcrystalline hydrogenated silicon of opto-electronic conversion.The mechanism that amorphous silicon converts microcrystal silicon to is that silicon is organized at first and begun to reconfigure at the interface of seeding layer when medium annealing, make young crystalline substance constantly enlarge, and this process helps infiltrate the help of hydrogen wherein again, high pressure has also been accelerated the process of crystallization simultaneously, the abundant environment of hydrogen makes the defective of grain surface in time obtain passivation, thus the higher electronic defects density that microcrystal silicon had of avoiding common direct growth to go out.Another advantage of this process is exactly that the silicon materials that plated can contain high relatively impurity, and does not influence the performance of microcrystal silicon, the interface zone of passivation because these impurity are ostracised, and do not play doping effect to crystal silicon.In order to enhance productivity, in a large-scale hyperbaric chamber, a lot of the substrates that are coated with silicon thin film can be handled simultaneously.

Description of drawings

The present invention will be further described below in conjunction with drawings and Examples.

Fig. 1 has shown a structure that is used to form the original material of microcrystal silicon.

Fig. 2 has shown that temperature is provided with in the high pressure that amorphous silicon is converted to microcrystal silicon.

Embodiment

The present invention has adopted one to be divided into the method that two steps obtained high-quality microcrystalline silicon.The first step method of plasma enhanced chemical vapor deposition, obtaining its bottom on substrate is the hydrogenation non crystal silicon film of seeding layer, and the growth rate of this amorphous silicon membrane is not less than 1 nm/sec, and thickness is no more than 3 microns.Second step as shown in Figure 2, be held in place on the support plinth with heating function 11 within the hyperbaric chamber 10 being placed on silane material 8 on the substrate 3, and introducing is not less than 500 atmospheric high pressure hydrogens 31 in the hyperbaric chamber, be not higher than under 300 ℃ the temperature, this anneal of material was handled 3-10 hour, thereby obtained being suitable for being used as the microcrystalline hydrogenated silicon of opto-electronic conversion.In high pressure medium annealing process, if hydrogenated silicon film by utilizing is to place among the device, then its two ends can be applied in a Dc bias 89, and the polarity of this voltage is selected according to the concrete structure of silicon device.In a same HIGH PRESSURE TREATMENT system, can place a plurality of substrates that are coated with silicon thin film.In the employed gases at high pressure, also can contain other gas that comprises inert gas, for example argon gas.

Claims

1. microcrystalline hydrogenated silicon film, this film thickness is no more than 3 microns, its average grain diameter is not less than 0.5 micron, it is characterized in that: its forming process is, be not less than in temperature on 200 ℃ the substrate, use plasma chemical vapor deposition, at first form a silane seeding layer that contains nucleus, on this layer, form a thickness then fast and be no more than 3 microns hydrogenation non crystal silicon film.This material is placed one subsequently and be not less than 500 atmospheric hydrogen gas environments,, keep 3-10 hour, thereby obtain being suitable for being used as the microcrystalline hydrogenated silicon of opto-electronic conversion not being higher than under 300 ℃ the temperature.

2. microcrystalline hydrogenated silicon film according to claim 1 is characterized in that: the silane seeding layer that contains nucleus of indication is p type or the n N-type semiconductor N film that is doped.

3. according to claim 1 or the described microcrystalline hydrogenated silicon film of claim 2, it is characterized in that: it has constituted the part of a photovoltaic device.