CN101777606B - Crystalline silicon solar battery selective diffusion process - Google Patents

Abstract

The invention belongs to the technical field of crystalline silicon solar battery preparation, in particular to a crystalline silicon solar battery selective diffusion process. The crystalline silicon solar battery selective diffusion process with simple process and low cost comprises the steps of concentrated phosphor diffusion, phosphorosilicate glass removal, printing corrosive agent etching and corrosive agent cleaning and removal. The solar battery prepared by the process has shallow emitter junctions with good surface passivation effect, high short wave effect can be obtained, at the same time, the battery obtains good ohmic contact because of the heavy doping in a grid line region, higher battery conversion efficiency can be obtained, and in addition, the process steps are simple. Compared with the traditional process, the invention needs to add less equipment.

Description

A kind of crystalline silicon solar battery selective diffusion process

Technical field

The invention belongs to the technical field of crystal-silicon solar cell preparation, be specifically related to a kind of crystalline silicon solar battery selective diffusion process.

Background technology

The solar cell diffusion technology trends towards preparing the short wavelength light response of shallow junction to obtain at present, but shallow doping meeting reduces the contact performance that prints electrode greatly, form good Ohmic contact except that improving the electrode slurry performance, must under electrode, carry out heavy doping, just under gate electrode line and near the highly doped dark diffusion region of formation, form low-doped shallow diffusion region in other zones, therefore how to realize that in zones of different shallow doping and heavy doping just become the problem that runs at present.The laboratory high-efficiency battery all adopts selective emitter basically at present, as the PERL battery, the PERT battery, bury grid cell etc., and the preparation method of its selective emitter mainly contains two kinds of methods: the one, adopt the silicon dioxide layer mask method, its processing step is: silicon chip cleaning and texturing → high-temperature oxydation → printing corrosivity slurry etching → slurry cleans to be removed → 30 ohm of dense phosphorous diffusions → oxide layer → 80 ohm of light phosphorous diffusion → edge etchings of removal and washes phosphorus, because of need increase multistep high-temperature technology and equipment, thereby make batch production technique loaded down with trivial details, production efficiency is low, and cost is very high, importantly the multiple high temp thermal process can produce harmful effect to the silicon chip performance, descends as minority carrier life time, silicon chip becomes fragile etc.; The 2nd, adopt photoetching or laser means, but, only rest on laboratory level because cost is higher.In addition, the use silk screen printing phosphorus paste-making method of also once reporting for work prepares selective emitter, is fit to suitability for industrialized production, but because the technology barrier that exists the phosphorus slurry to prepare is failed large-scale application, thereby its industrialization is restricted.

Summary of the invention

The objective of the invention is at the defective of above-mentioned existence and the crystalline silicon solar battery selective diffusion process that a kind of technology is simple, cost is low is provided, the shallow emitter junction that the solar cell of this prepared has the excellent surface passivation can obtain high short wave response, heavy doping in grid region simultaneously makes battery obtain good Ohmic contact, obtain higher battery conversion efficiency, and this processing step is simple, and process equipment is few.

Crystalline silicon solar battery selective diffusion process of the present invention: comprise the steps:

(1) dense phosphorous diffusion;

(2) phosphorosilicate glass is removed;

(3) printing corrosive agent etching;

(4) cleaning of corrosive agent is removed.

Wherein, described corrosive agent is the corrosivity slurry that contains the hydrogen fluoride ammonia of 20-30% concentration, and described concentration is mass ratio.

Detailed process step of the present invention is:

(1) silicon chip behind the cleaning and texturing is carried out the dense phosphorous diffusion of high temperature, diffusion back square resistance is 30-40 ohm;

(2) silicon chip after the phosphorous diffusion adopts the hydrofluoric acid solution of 5-10% to clean 5-10min, removes phosphorosilicate glass;

(3) it is corroded at non-gate electrode line zone printing corrosivity slurry according to the web plate figure, place air at room temperature to stop 2-3min the silicon chip that prints the corrosivity slurry, corrosion thickness is 200-300nm, and the corrosion of the square resistance in non-gate electrode line zone is 80-100 ohm;

(4) silicon chip after will corroding is used deionized water rinsing 5-10min once more with deionized water ultrasonic cleaning 3-5min.

Beneficial effect of the present invention is: compare with traditional handicraft, the shallow emitter junction of prepared of the present invention has good short wave response, battery short circuit electric current and open circuit voltage have been improved, electrode district heavy doping simultaneously can make between metal and silicon chip and form good Ohmic contact, higher battery fill factor, curve factor can be obtained, therefore higher battery conversion efficiency can be obtained.

Compare with other selective diffusion process technology, processing step and process equipment that the present invention increases are less, and technological operation is simple relatively, and production cost is relatively low; And only High temperature diffusion technical process has once reduced the harmful effect of elevated temperature heat process to the silicon chip performance, can guarantee to obtain higher battery conversion efficiency.

Embodiment

Below in conjunction with specific embodiment technical scheme of the present invention is described in detail.

Embodiment 1

Silicon slice placed behind the cleaning and texturing is carried out the dense phosphorous diffusion of high temperature in tubular diffusion furnace, diffusion back square resistance is 30 ohm; Adopt 5% hydrofluoric acid solution cleaning 10min then, remove phosphorosilicate glass; It is corroded at the hydrogen fluoride ammonia corrosion slurry that the zone printing of non-gate electrode line contains 20% concentration according to the web plate figure again, place air at room temperature to stop 2min the silicon chip that prints corrosive slurry, is 80 ohm with the square resistance in non-gate electrode line zone by 30 ohm of original corrosion, 30 ohm of gate electrode line zone square resistance maintenances are constant, and corrosion thickness is controlled at 200nm; Silicon chip after will corroding is again used deionized water rinsing 10min once more with deionized water ultrasonic cleaning 5min; Cleaned silicon chip carries out follow-up etching again, technologies such as plating antireflective film, electrode printing and sintering obtain solar cell.

Embodiment 2

Silicon slice placed behind the cleaning and texturing is carried out the dense phosphorous diffusion of high temperature in the chain type diffusion furnace, diffusion back square resistance is 40 ohm; Adopt 10% hydrofluoric acid solution cleaning 5min then, remove phosphorosilicate glass; It is corroded at the hydrogen fluoride ammonia corrosion slurry that the zone printing of non-gate electrode line contains 30% concentration according to the web plate figure again, place air at room temperature to stop 3min the silicon chip that prints corrosive slurry, is 100 ohm with the square resistance in non-gate electrode line zone by 40 ohm of original corrosion, 40 ohm of gate electrode line zone square resistance maintenances are constant, and corrosion thickness is controlled at 300nm; Silicon chip after will corroding is again used deionized water rinsing 5min after using deionized water ultrasonic cleaning 3min once more; Cleaned silicon chip carries out follow-up etching again, technologies such as plating antireflective film, electrode printing and sintering obtain solar cell.

Claims (2)

1. crystalline silicon solar battery selective diffusion process, its processing step is:

(1) silicon chip behind the cleaning and texturing is carried out the dense phosphorous diffusion of high temperature, diffusion back square resistance is 30-40 ohm;

(2) silicon chip after the phosphorous diffusion adopts the hydrofluoric acid solution of 5-10% to clean 5-10min, removes phosphorosilicate glass;

(3) it is corroded at non-gate electrode line zone printing corrosivity slurry according to the web plate figure, place air at room temperature to stop 2-3min the silicon chip that is printed with the corrosivity slurry, corrosion thickness is 200-300nm, and the corrosion of the square resistance in non-gate electrode line zone is 80-100 ohm;

(4) silicon chip after will corroding is used deionized water rinsing 5-10min once more with deionized water ultrasonic cleaning 3-5min.

2. crystalline silicon solar battery selective diffusion process according to claim 1 is characterized in that, described corrosivity slurry is the hydrogen fluoride ammonia that contains 20-30% concentration, and described concentration is mass ratio.