CN102102192A - Method for promoting crystallization of silicon film on glass substrate by using light with specific wavelength - Google Patents

Abstract

The invention belongs to the technical field of optics, and relates to a method for promoting the crystallization of a silicon film on a glass substrate by using light with a specific wavelength. The method comprises the following steps of: a, pretreating a substrate material; b, preparing an amorphous silicon film; and c, preparing a polycrystalline silicon film. Compared with the conventional method, the method has the advantages that: light which is favorable for the crystallization and has the controllable wavelength is used for irradiating, so the crystallization effect of the silicon film, and the efficiency and stability of a silicon film battery can be improved; and light with other residual frequencies and harmful heat energy in the conventional illumination method are removed, so the indoor temperature is reduced, low-cost glass with low softening point can be used, and production cost is reduced. In a word, by the method, the preparation process of a silicon film solar battery is simple, and the production cost is reduced.

Description

On glass substrate, utilize the light of specific wavelength to promote silicon film crystalline method

Technical field

The invention belongs to optical technical field, relate to a kind of light of specific wavelength that on glass substrate, utilizes and promote silicon film crystalline method.

Background technology

The preparation film is the technique direction that opto-electronics, field of semiconductor materials are often used on glass substrate, glass has good light transmission, with low cost, has certain intensity, can anti-certain high temperature, and be a kind of material of construction, preparation high-quality thin-film great commercial value on the glass substrate of cheapness.People by conventional resistance wire heat, methods such as halogen tungsten lamp heating and laser scanning again crystallization do crystalline membrane.Height by treatment temp is divided, and is divided three classes at present: low temperature process, middle temperature technology and high-temperature technology.In general, high-temperature technology is prepared oarse-grained silicon film easily, still, is difficult at present find at the bottom of a kind of free of contamination high temperature-resistant liner of cheapness, and power consumption is high in addition, cost high (such as using laser crystallization); With regard to low temperature process, film crystal grain is less, defective is more, photoelectric properties are relatively poor.Because the restriction that the simple glass strain point is low, so wish usually under lower temperature, to obtain the better film of crystallization effect.

Summary of the invention

The objective of the invention is to overcome deficiency of the prior art and provide a kind of crystallization effect good, technology is simple, the silicon film crystalline method that production cost is low.

The object of the present invention is achieved like this: a kind of light of specific wavelength that utilizes on glass substrate promotes silicon film crystalline method, comprises the steps:

A, sink to the bottom the pre-treatment of material: will clean clean silica glass oven dry back as substrate, and be positioned in the sediment chamber of plasma CVD device and do next step processing;

The preparation of b, amorphous silicon membrane: earlier the sediment chamber is evacuated to 4 ~ 6 * 10 ^-4Pa, mixture with reactant gas silane and hydrogen feeds in the sediment chamber then, makes that the thinning ratio of hydrogen is 95%, is that 2cm and discharge power are under the condition of 50 ~ 60W in interelectrode distance, carry out radio frequency glow discharge and decompose silane and hydrogen, thereby on silica glass, deposit one deck amorphous silicon membrane; Substrate temperature is 100 ~ 300 ℃ during deposition, and operating air pressure is 133.3Pa, and depositing time is 2 ~ 3 hours, and film thickness is 0.5 ~ 1 μ m;

The preparation of c, polysilicon membrane: above-mentioned amorphous silicon membrane is positioned in the photo-annealing stove, with nitrogen as shielding gas, and vacuum tightness is 5.6 * 10 ^-4Under the Pa condition, be 1.2 * 10 with frequency ¹⁴Hz and 2 * 10 ¹⁵The light of Hz carries out uniform irradiation to silicon film, makes temperature to 700 ~ 900 ℃ of silicon film, and annealing insulation 1 ~ 30min naturally cools to 20 ~ 25 ℃ then, promptly obtains polysilicon membrane on silica glass.

The present invention has following advantage: the inventive method is compared with traditional method, uses the rayed that helps crystallization, can control wavelength, can improve the crystallization effect of silicon film on the one hand, improves the efficient and the stability of silicon thin-film battery; On the other hand because removed the light and the deleterious heat energy of other unnecessary frequencies in traditional illumination method, thus room temp reduced, thus can use cheap low softening point glass, reduce production costs.In a word, present method makes the simple and production cost reduction of preparation silicon film solar batteries technology.

Embodiment

A kind of light of specific wavelength that utilizes on glass substrate promotes silicon film crystalline method, comprises the steps:

A, sink to the bottom the pre-treatment of material: will clean clean silica glass oven dry back as substrate, and be positioned in the sediment chamber of plasma CVD device and do next step processing;

The preparation of b, amorphous silicon membrane: earlier the sediment chamber is evacuated to 5.6 * 10 ^-4Pa, mixture with reactant gas silane and hydrogen feeds in the sediment chamber then, makes that the thinning ratio of hydrogen is 95%, is that 2cm and discharge power are under the condition of 50 ~ 60W in interelectrode distance, carry out radio frequency glow discharge and decompose silane and hydrogen, thereby on silica glass, deposit one deck amorphous silicon membrane; Substrate temperature is 100 ~ 300 ℃ during deposition, and operating air pressure is 133.3Pa, and depositing time is 2 hours, and film thickness is 0.5 ~ 1 μ m;

The preparation of c, polysilicon membrane: above-mentioned amorphous silicon membrane is positioned in the photo-annealing stove, with nitrogen as shielding gas, and vacuum tightness is 5.6 * 10 ^-4Under the Pa condition, be 1.2 * 10 with light frequency ¹⁴Hz and 2 * 10 ¹⁵The halogen tungsten lamp of Hz carries out uniform irradiation to silicon film, and when the temperature to 850 of silicon film ℃, annealing 1min naturally cools to 20 ~ 25 ℃ then, promptly obtains uniform polysilicon membrane on silica glass; When the temperature to 750 of silicon film ℃, annealing 15min naturally cools to 20 ~ 25 ℃ then, and crystallization rate can reach 75%.

Principle of work of the present invention: (1) adopts how low temperature deposit amorphous silicon membrane of radio frequency glow discharge principle.(2) to be converted into polysilicon membrane be that silicon hydrogen atom group interacts with light to amorphous silicon membrane, the result who vibration takes place or rotate, the energy that provides when illumination and si-h bond division and molecular vibration rotate the energy that needs easier generation resonance absorption when suitable, thereby the energy state transfer takes place.From amorphous to the process that polycrystalline transforms, the kinestate of Si:H is mainly the vibration and the rotation of molecule.And the vibration of molecule and rotational energy all are quantized.Can calculate the energy that vibration or rotational level transition needs take place for it according to the schroedinger equation that the Hamiltonian of correspondence is represented for diatomic Si:H, corresponding this energy can be determined required irradiation light wavelength and frequency.(3) light of selecting approximate sunlight for use can be found out the temperature of the energy correspondence of the division of Si:H key, silicon hydrogen molecule vibration rotation needs according to solar spectrum as light source.At logical nitrogen protection gas, under the vacuum condition, the Si film according to for some time, naturally cools to room temperature and just can obtain desired sample under this temperature.(4) carrying out photo-annealing with the sedimentary amorphous silicon membrane of PECVD method with the rayed of specific wavelength compares greatly with conventional annealing and has saved the time.Conventional annealing is the heat energy that discharges by resistive heater, the energy of providing conversion to need for the Siliciumatom in the amorphous silicon membrane, the heat energy that is discharged during resistive heater is the energy of various energy levels from low to high, the ratio that the energy that wherein really suits the requirements accounts for total energy is not high, therefore, the energy that enough really suits the requirements is arranged, must prolong heat-up time.Photo-annealing is to realize by large-area illumination, and the photo-annealing mode provides the energy that needs more direct, and it is easier to make noncrystalline membrane forward the polycrystalline state film to, and the time that needs is many with regard to weak point.The conventional annealing time is long, and the sufficient movement collision of Siliciumatom group is so the film crystal grain after the annealing condenses together skewness; Adopting photo-annealing is by large-area illumination, and the time is short, and the crystal grain of the polysilicon membrane that the annealing back obtains distributes more even, and structure is level and smooth.

Claims (1)

1. one kind is utilized the light of specific wavelength to promote silicon film crystalline method on glass substrate, it is characterized in that: comprise the steps:

A, sink to the bottom the pre-treatment of material: will clean clean silica glass oven dry back as substrate, and be positioned in the sediment chamber of plasma CVD device and do next step processing;

The preparation of b, amorphous silicon membrane: earlier the sediment chamber is evacuated to 4 ~ 6 * 10 ^-4Pa, mixture with reactant gas silane and hydrogen feeds in the sediment chamber then, makes that the thinning ratio of hydrogen is 95%, is that 2cm and discharge power are under the condition of 50 ~ 60W in interelectrode distance, carry out radio frequency glow discharge and decompose silane and hydrogen, thereby on silica glass, deposit one deck amorphous silicon membrane; Substrate temperature is 100 ~ 300 ℃ during deposition, and operating air pressure is 133.3Pa, and depositing time is 2 ~ 3 hours, and film thickness is 0.5 ~ 1 μ m;

The preparation of c, polysilicon membrane: above-mentioned amorphous silicon membrane is positioned in the photo-annealing stove, with nitrogen as shielding gas, and vacuum tightness is 5.6 * 10 ^-4Under the Pa condition, be 1.2 * 10 with frequency ¹⁴Hz and 2 * 10 ¹⁵The light of Hz carries out uniform irradiation to silicon film, makes temperature to 700 ~ 900 ℃ of silicon film, and annealing insulation 1 ~ 30min naturally cools to 20 ~ 25 ℃ then, promptly obtains polysilicon membrane on silica glass.