Rec - Improves Diffusion Process Cost - REC Group

Rec - Improves Diffusion Process Cost

eysteinh

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Sunday, April 7th 2013, 1:20am

Rec - Improves Diffusion Process Cost

Details of the agrement:
http://www.centrotherm-pv.com/en/press/n…5BbackPid%5D=92

"centrotherm photovoltaics won out against its competitors with its 5-chamber diffusion furnace, which not only offers outstanding phosphorus diffusion capabilities, but also enables the reliable implementation of higher resistance emitters on a low-cost basis"

(edited because this is in fact a p-type based diffusion)

Major advantags of the n-type:
they do not suffer from light induced degradation (LID)
n-type Si wafers are less sensitive to impurities that are usually present in silicon feedstock. Basically during the doping of phosphorus many of the metal impurities will disolve so it is well suited for solar grade polyislicon.
N-type has in studies shown to give a few percentage absolute cell effiency increase and a handfull of cents in cost savings on production, but at added cost. I speculate that Rec has purchased the euqipment cheaply since it is a downturn period in the industry.

The equipment purchased I belive is a Centrotherm E2000LP with 5 tube design. Capacity with feeding from two directions at same time is around 3500 wafers, waffernty is 1 year and suggested price in photon international nr 8 2012 was around 1,1-1,5 millon.

previously one of the first movers to n-type was yingli with the panda modules, and trina solar also has n-type production.

The LG2000LP with an almost vacum like process is well regarded to give little mechanical stress on the wafers, it is also well suited for following the technology path of selective emitter designs. It also has a very uniform resistance on doping from wafer to wafer with +- 2 ohm and is well suited for having a doping process that causes less of a "dead layer" that has to be removed during texturing.

This post has been edited 4 times, last edit by "eysteinh" (Apr 7th 2013, 10:21am)

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solarcat

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Sunday, April 7th 2013, 7:18am

eysteinh, May I ask a question? Are N-type wafers some proprietary technology, or equipment companies like Centrotherm are offering the technology to everyone? And if it is not a proprietary technology, what is to prevent every wafer currently being produced from being a N-type wafer?

I guess what I'm asking is, does the solar industry have patents and proprietary differentiation or does everyone buy the same equipment from the same equipment manufacturers to produce next generation commodity parts?

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odyd12

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Sunday, April 7th 2013, 8:27am

Quoted from "eysteinh"

which not only offers outstanding phosphorus diffusion capabilities, but also enables the reliable implementation of higher resistance emitters on a low-cost basis"

Phosphorus emitter is made on boron doped wafer. This equipment makes p-type based cells.

Phosphorus "n" is introduced to p (hence p-type wafer) boron to form p-n junction in process of difussion.

In n-type wafer, phosphorus is the dopant. The boron is diffused on it to create n-p junction.
As far as I can read this this is conventional type oven which helps with selective emitter.

Solarcat, n-type wafers are made by at least 3 capable manufacturers. Nexolon, Solargiga and Comtec makes them. SunPower's and Panasonic's modules are based on n-type and so is Panda. SunPower buys Chinese wafers to make them into their powerful modules, and SPWR and the media describes its huge differentiation without hardly giving credit to anyone or public knowing true origin. Sure their copper metalization is ahead of the game too but...Yingli makes on n-type wafers.
Certainly as Eysteinh described they are unique and very capable.
Read my interview with ECN for more details and site has plenty of articles about it. In this industry ability to master cost is the first condition and that makes differentiation.
On manufacturing
https://solarpvinvestor.com/spvi-news/88-…ll-technologies

https://solarpvinvestor.com/spvi-news/91-…le-expectations

on ECN interview
https://solarpvinvestor.com/spvi-news/444…y-as-a-solution

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eysteinh

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Sunday, April 7th 2013, 9:54am

Are N-type wafers some proprietary technology, or equipment companies like Centrotherm are offering the technology to everyone? And if it is not a proprietary technology, what is to prevent every wafer currently being produced from being a N-type wafer?

The N-type is just a way of doping, see what odyd writes. How you use the N-type and your designs could be patented and different. Keep in mind the terminology can be mixed up and I have seen it used the complete opposite way in many research reports. For me an N-type wafer is a wafer doped with phosphorus substances instead of boron. The ingot was made and doped with boron. (P-type) then the emittor layer is made of doping boron to form a P-N junction as an basis of electricity.

But more important the companies who have planned for this or have the cash to do the upgrades should do better than those who cannot keep pace with the effiency increases: I am not saying there are not other routes to take to high effiency all I am saying is most of the high effiency based modules now are N-type emittor based.

This post has been edited 4 times, last edit by "eysteinh" (Apr 7th 2013, 10:08am)

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Klothilde

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Sunday, April 7th 2013, 10:03am

Thanks guys, now you got me confused.

According to my understanding REC is NOT moving to n-type wafers but has purchased equipment for selective emitter technology on p-type wafers.

Is this correct? Then the title of the Fred is erroneous and should be changed.

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eysteinh

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Sunday, April 7th 2013, 10:20am

Thats correct, I read an article with the different terminology but I have cheched with two other articles now and indeed its usually boron based silicon that is doped with phosphorus.

The n wafer is the opposite, phosphorus based silicon doped with boron.

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explo

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Sunday, April 7th 2013, 11:11am

Quoted from "Klothilde"

According to my understanding REC is NOT moving to n-type wafers but has purchased equipment for selective emitter technology on p-type wafers.

Thanks. I was also confused, since the Centrotherm PR talks about upgrade of all existing production lines and those are primarily DSS based on the ingot side to my knowledge.

So it's some improvement of how cells are made from p-type multi wafers, right? Now can we get more info about the significance of this improvement? Will it compete with Trina's Honey?

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odyd12

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Sunday, April 7th 2013, 12:14pm

Quoted from "eysteinh"

Thats correct, I read an article with the different terminology but I have cheched with two other articles now and indeed its usually boron based silicon that is doped with phosphorus.

The n wafer is the opposite, phosphorus based silicon doped with boron.

P-type wafer is made by doping polysilicon with boron. This wafer then is diffused with layer of phosphorus. This junction is called p-n junciton
N-type wafer is doped with phosphorus, and has boron diffused onto it. This junction is called n-p junction.
REC is going to use it for its phosphorus diffusion, nothing of n-type.

@Explo, centotehrm furnaces offer both materials for diffusion using BBr3 and POCI3,
Their intro
"The unique advantages of the batch-type system are the high flexibility towards varying production load and process sequence as well as the continued operation in case of tube maintenance or shut-down. Various configurations regarding process capability, capacity and automation level are available.
• Throughput gain of 15 – 25 % compared to standard system
• Diffusion on both wafer sides (extended gettering effect of phosphorus improves material quality)
• High availability due to redundancy
• Highest cleanness (gas phase diffusion without residues)
• System configuration adjustable to production capacity (number of tubes, optional back-to-back loading)
• Fully automated boat handling guarantees maximized tube utilization
• Modular design allows easy installation and start-up
• Up to 5 independently operated stacked quartz tube reactor chambers
• No thermal interference between different tubes due to advanced water cooling system
• Minimized footprint and facility heat load reduce total cost of ownership"

Cost improvement when using diffusion, by cheaper way to bind emitters, whihc would result in better selective emitter outcome
http://www.centrotherm-pv.com/de/product…technology.html

in our interview with Trina
https://solarpvinvestor.com/spvi-news/265…-the-sweet-spot

Honey has all of it, so it is a matter of REC improving further its cost and obviously naturally doing so wit this purchase.
Now I suspect that Trina has not sat on its hands for all this time, and moved its cost lower but what they have done is not known to me.

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eysteinh

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Sunday, April 7th 2013, 2:01pm

Quoted from "odyd12"

P-type wafer is made by doping polysilicon with boron. This wafer then is diffused with layer of phosphorus. This junction is called p-n junciton
N-type wafer is doped with phosphorus, and has boron diffused onto it. This junction is called n-p junction.
REC is going to use it for its phosphorus diffusion, nothing of n-type.

Yeah thats what I was trying to say

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eysteinh

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Tuesday, April 9th 2013, 4:27pm

http://qz.com/72590/sol-voltaics-can-a-s…solar-industry/

"That’s the length of a gallium arsenide nanowire that Swedish startup Sol Voltaics has invented. The company claims a layer of nanowires added to a conventional solar panel can boost its efficiency by as much as 25%."

Capital costs are low as well. Sol Voltaics has raised $11 million from European investors, including Alf Bjørseth, the founder of Norway’s REC Solar, one of the world’s largest solar manufacturing companies.

Rec is not founding but with the former founder of REC i think there is a chance they will go for this technology.

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eysteinh

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Tuesday, April 9th 2013, 4:32pm

http://www.pv-magazine.com/services/pres…/#axzz2PEnDaRVj

A bit like smartwire technology from meyer burge. A mesh put on top of the module instead of circuts printed on.

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eysteinh

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Friday, April 12th 2013, 7:02am

Actually after reading even more scientific articles N-type wafers can be made of other materials too. N-type has more electrons and thus cause movement of holes left when electrones move over to p-type side of junction with less electrons.

For example L.J. Geerligs, N. Guilevin & I.G Romijn, ECN Solar Energy, Petten, The netherlands (2012) discuss progression of n-type base crystalion silicon solar cells. "An alternative process to create n-type cells by a relatively simple process is by applying phosphorous front diffusion and AI-alloying on the rear."