CN203351628U

CN203351628U - Low-surface recombination solar cell

Info

Publication number: CN203351628U
Application number: CN2013204302143U
Authority: CN
Inventors: 陆俊宇; 魏青竹; 连维飞; 张风雷; 王志刚; 易辉; 汪燕玲
Original assignee: Zhongli Talesun Solar Co Ltd
Current assignee: Suzhou Talesun Solar Technologies Co Ltd
Priority date: 2013-07-19
Filing date: 2013-07-19
Publication date: 2013-12-18
Anticipated expiration: 2023-07-19

Abstract

The utility model is to provide a production method for a low-surface recombination solar cell, so that under the condition that the advantages, such as easy process and low cost, of square resistance technology are retained, the disadvantages that surface doping density is difficult to control, the influence of a surface dead layer cannot be completely avoided, and when the square resistance is made high, the uniformity cannot be guaranteed are overcome.

Description

A kind of low surface recombination solar cell

Technical field

The utility model relates to the photovoltaic field, is specifically related to a kind of low surface recombination solar cell.

Background technology

Low-cost, high efficiency is the developing direction of current crystal silicon solar energy battery.Reduce the doping content of light area, reduce surface recombination and can effectively promote the short-wave band photon efficiency, blue response is good, and current density is high, thereby promotes battery performance, is one of effective way improved battery efficiency.Mainly contain at present following technology and can reach the reduction doping content, reduce the purpose of surface recombination: selective emitter technology, high square resistance technology, ion implantation technique.Be subject in the past the impact of golden half contact quality, for uniform emission utmost point battery, the doping content of front side silver paste contact area can not be done very lowly, the selective emitter technology developed under background at that time can not be subject to the restriction of golden half contact quality, surface doping concentration is done low, but its technological process is relatively complicated, technological requirement is higher, need interpolation equipment or original product line is transformed, cost is higher.And the development along with Size Technology, front side silver paste can form good ohmic contact with the more and more lower surface of doping content, simple, with low cost high square resistance technology that a lot of enterprises are more prone to technique, what the cell piece of most enterprises production adopted at present is all the high square resistance technical matters.The high square resistance technical matters is simple, with low cost, and the silver slurry of appropriate mix, can promote battery efficiency.But sheet resistance is done height, knot is done when shallow, generally can reduce TongYuan's amount, reduce temperature, reduce the process time, surface doping concentration and junction depth all are difficult to control in this case, and uniformity also is difficult to assurance; Should guarantee that surperficial doping content considers junction depth again, both are difficult to reach ideal conditionss simultaneously simultaneously; This technique can't be avoided the impact of surface " dead layer " (inactive layer) fully in addition; Above some all can badly influence the effect of improved efficiency.Although ion implantation technique can be to doping content, junction depth is accurately controlled, and uniformity is also fine, needs to add ion implantation device, with high costs.

The utility model content

For solving the problems of the technologies described above, the purpose of this utility model is to provide a kind of low surface recombination solar cell, make in reservation high square resistance technical matters simple, overcoming its surperficial doping content in advantage situation with low cost is difficult to control, can't avoid the impact of surperficial dead layer fully, sheet resistance is done uniformity when high and is difficult to the shortcoming guaranteed.

For achieving the above object, the technical solution of the utility model is as follows: a kind of low surface recombination solar cell, be disposed with from down to up: silicon base, diffusion layer, anti-reflection rete, on the anti-reflection rete, sintering has positive electrode, and described positive electrode and described diffusion layer electrically contact.

Preferably, described low surface recombination solar cell is high square resistance and low surface concentration, and its sheet resistance reaches 70 ~ 120 Ω/, and the surface concentration size is between 1E20 ~ 5E20.

By following steps, prepared by the utility model:

The first step, former silicon wafer wool making;

Second step, after making herbs into wool, be different from common high square resistance technique, adopts low square resistance, deeply ties technique and spread, and diffused sheet resistance is more even;

The 3rd step, after diffusion, the back side and edge PN junction etching, remove PSG;

The 4th step, process with HF/HNO3 mixed solution or dilute NaOH solution after etching, removes dead layer; Reduce surperficial doping content

The 5th step, the plating antireflective film;

The 6th step, silk screen printing, sintering.

Preferably, in described second step, the diffusion technology of described employing low square resistance, dark knot, sheet resistance is controlled at 30 ~ 60 Ω/, and junction depth is controlled at 0.3 ~ 0.6um.

Preferably, in described the 4th step, in described HF/HNO3 mixed solution, the volume ratio of HF/HNO3 is 1:3 ~ 1:10, and described dilute NaOH solution concentration is 0.1% ~ 2%.

Preferably, in the 4th step, in the situation of fixed solution concentration, by the adjusting process time, adjust etching extent, thereby final surface doping concentration is accurately controlled.

Preferably, by increasing TongYuan's amount, the source amount is reached capacity, improve diffusion temperature simultaneously, increase diffusion time, can greatly improve like this uniformity of sheet resistance, junction depth is controlled by technological temperature or time, in the situation that junction depth is done deeply and do not considered surface concentration, junction depth is easily controlled.

Adopt technique scheme, the beneficial effect of technical solutions of the utility model is: adopt the diffusion technology of low square resistance, dark knot at second step, by increasing TongYuan's amount, the source amount is reached capacity, improve diffusion temperature simultaneously, increase diffusion time, can greatly improve like this uniformity of sheet resistance.Junction depth is controlled by technological temperature or time, in the situation that junction depth is done deeply and do not considered that surface concentration, junction depth ratio are easier to control.Increase by the 4th step on common process, adopt HF/HNO3 mixed solution or rare NaOH solution that the dead layer of silicon chip surface is eroded, reduce surperficial doping content.

In the situation that fixed solution concentration is adjusted etching extent by the adjusting process time, thereby final surface doping concentration is accurately controlled.Most equipment possesses the transformation condition at present, by simple equipment and technology adjustment, the 4th step can be integrated in the 3rd step, and technique is simpler, operates easier.

The utility model is to possess the high square resistance technical matters simple, and the prerequisite lower surface doping content of advantage with low cost is more accurate in controlling, and can avoid the impact of dead layer, and the uniformity of sheet resistance is also better, and battery efficiency promotes more obvious.

The accompanying drawing explanation

In order to be illustrated more clearly in the technical scheme in the utility model embodiment technology, below will the accompanying drawing of required use in the embodiment technical description be briefly described, apparently, accompanying drawing in the following describes is only embodiment more of the present utility model, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain according to these accompanying drawings other accompanying drawing.

Fig. 1 is the structural representation of the utility model in second step.

Fig. 2 is the structural representation of the utility model in the 3rd step.

Fig. 3 is the structural representation of the utility model in the 4th step.

Fig. 4 is that the utility model is the structural representation of product in the 6th step.

Wherein, legend:

Silicon base, 2. diffusion layer, 3. " dead layer " (inactive layer), 4.PSG,

5. antireflective film, 6. positive electrode

Annotate: 1., 2., 3., 4., 5., 6. number in the figure distinguishes corresponding 1,2,3,4,5,6.

Embodiment

Below in conjunction with the accompanying drawing in the utility model embodiment, the technical scheme in the utility model embodiment is clearly and completely described, obviously, described embodiment is only the utility model part embodiment, rather than whole embodiment.Embodiment based in the utility model, those of ordinary skills are not making under the creative work prerequisite the every other embodiment obtained, and all belong to the scope of the utility model protection.

As Fig. 1, to as shown in Fig. 4, a kind of low surface recombination solar cell, is characterized in that, is disposed with from down to up: silicon base 1, diffusion layer 2, anti-reflection rete 5, and on the anti-reflection rete, sintering has positive electrode 6, and described positive electrode 6 electrically contacts with described diffusion layer 2.

Its manufacture method comprises the following steps:

The first step, former silicon wafer wool making;

Second step, after making herbs into wool, be different from common high square resistance technique, adopts low square resistance, deeply ties technique and spread, and diffused sheet resistance is more even; Sheet resistance is controlled at 40 Ω/, and junction depth is controlled at 0.4um.

The 3rd step, after diffusion, the back side and edge PN junction etching, remove PSG4;

The 4th step, process with HF/HNO3 mixed solution or dilute NaOH solution after etching, removes dead layer (inactive layer) 3; Reduce surperficial doping content; In described HF/HNO3 mixed solution, the volume ratio of HF/HNO3 is 1:5, or adopts the dilute NaOH solution of 0.5% concentration.

The 5th step, the plating antireflective film;

The 6th step, silk screen printing, sintering.

In the above-described embodiments, in described second step, the diffusion technology of described employing low square resistance, dark knot, according to actual needs, sheet resistance can be controlled in the arbitrary numerical value between 30 ~ 60 Ω/, as 31 Ω/, 32 Ω/, 33 Ω/ ... 57 Ω/, 58 Ω/, 59 Ω/, junction depth is controlled at the arbitrary numerical value between 0.3 ~ 0.6um, as 0.31um, 32um ... 0.57um, 0.58um, 0.59um.

In the above-described embodiments, in described the 4th step, according to actual needs, in described HF/HNO3 mixed solution, the volume ratio of HF/HNO3 can be chosen to be the arbitrary numerical value between 1:3 ~ 1:10, as 1:4,1:5 ... 1:8,1:9, the controlled arbitrary numerical value be made as between 0.1% ~ 2% of described dilute NaOH solution concentration, as 0.2%, 0.3% ... 1.8%, 1.9%.

In the 4th step, adjust etching extent by the adjusting process time in the situation of fixed solution concentration, thereby final surface doping concentration is accurately controlled.

In second step, by increasing TongYuan's amount, the source amount is reached capacity, improve diffusion temperature simultaneously, increase diffusion time, can greatly improve like this uniformity of sheet resistance, junction depth is controlled by technological temperature or time, in the situation that junction depth is done deeply and do not considered surface concentration, junction depth is easily controlled.

A kind of low surface recombination solar cell made by above-described embodiment is disposed with from down to up: silicon wafer layer, diffusion layer, anti-reflection rete, and on the anti-reflection rete, sintering has positive electrode, and described positive electrode and described diffusion layer electrically contact.

Wherein, the battery sheet resistance reaches 70 ~ 120 Ω/, and the surface concentration size is between 1E20 ~ 5E20.

Said method and the product made thereof have the following advantages:

1), battery efficiency effectively promotes.

2), only need existing production technology is simply adjusted method simple possible with low cost.

3), the sheet resistance good uniformity, can the effects on surface doping content and junction depth accurately control.

To the above-mentioned explanation of the disclosed embodiments, make professional and technical personnel in the field can realize or use the utility model.Multiple modification to these embodiment will be apparent for those skilled in the art, and General Principle as defined herein can be in the situation that do not break away from spirit or scope of the present utility model, realization in other embodiments.Therefore, the utility model will can not be restricted to these embodiment shown in this article, but will meet the widest scope consistent with principle disclosed herein and features of novelty.

Claims

1. one kind low surface recombination solar cell, is characterized in that, is disposed with from down to up: silicon base, diffusion layer, anti-reflection rete, and on the anti-reflection rete, sintering has positive electrode, and described positive electrode and described diffusion layer electrically contact.

2. low surface recombination solar cell according to claim 1, is characterized in that, described low surface recombination solar cell is high square resistance and low surface concentration, and its sheet resistance is 70 ~ 120 Ω/, and the surface concentration size is between 1E20 ~ 5E20.