N-Type Silicon's Invisible Efficiency Killer: Lokacin da Oxygen Ya Wuce 12 ppma, Cells Suna Rasa 0.4%+

Gabatarwar Samfur

Wani injiniyan tsari ya taɓa bayyana mini wannan yanayin.

Wata rana, hoton PL daga binciken samfurin boron-diffusion ya nuna wasu ƴan wafers da ke da bayyanannun zoben da'ira masu layu. Tunaninsa na farko shine ya ja bayanan binciken shigowa na wannan batch: rayuwar 'yan tsiraru masu ɗaukar nauyi sama da 1500 μs, iskar oxygen precipitate absorbance ta wuce, micro-defect density a cikin spec. A takarda, kowane haske kore ne.

Ya kira lab don sake duba EBIC na yau da kullun. Babu abin da ya bayyana. Ya canza zuwa preferential etching tare da optical microscopy. Har yanzu babu komai.

Amma waɗannan zobba a kan taswirar PL suna nan a wurin. Ba su ɓace ba.

Binciken shigowa ya wuce, sake dubawa bai sami komai ba, kuma PL har yanzu yana nuna da'irar duhu. Wannan rashin daidaituwa uku shine ɗaya daga cikin mafi yawan asarar shiru da injiniyan tsari na N-type ke fuskanta.

Abokin hamayyar da ke bayansa shine abin da wannan labarin ya rarraba: concentric ring defects (CRD) a cikin N-type photovoltaic Czochralski single-crystal silicon. Yana ɗaya daga cikin mafi ƙarancin kisa na yawan amfanin ƙasa a cikin sel N-type, kuma a cikin mafi munin yanayi zai iya cinye 4% absolute cell efficiency.

Daga P-Type zuwa N-Type, Injiniyoyi Sun Canza Abokan Hamayya

Bari mu fayyace abu ɗaya tukuna.

A zamanin P-type, babban tsohon abokin hamayya a gefen wafer shine boron-oxygen pair (BO defect): tantanin B-Cz PERC a ƙarƙashin haske na sa'o'i 12 na iya rasa 3-5% cikakken (lambar da aka sake dubawa a cikin karatun PhD na Vicari Stefani na 2022). P-type multicrystalline silicon kuma yana da LeTID, wanda a mafi munin yanayi zai iya raguwa 16%. Masana'antar gabaɗaya ta shafe fiye da shekaru goma tana yaƙi da waɗannan asarar da haske ke haifarwa, daga gyare-gyaren tsarin PERC zuwa UV-filtering encapsulants a gefen module.

A canjin N-type, masana'antar ta taɓa tunanin wannan yaƙin ya ƙare. Wafer N-type an yi su da phosphorus-doped, don haka babu tilas B×O pairing kuma BO defect ba zai iya samuwa ba.

Amma mutane ba da daɗewa ba suka gano: BO ya ɓace, kuma oxygen precipitates (OP) sun tashi da kansu. Sun sanya wani ɓoyayyen ɓoyayyen wannan lokacin: concentric ring defects.

Li Guixiu daga Jami'ar Zhejiang (a cikin rukunin Farfesa Yuan Shuai) ya gabatar da wannan a taron CSPV na 21 a 2025, kuma ya buga aikin da ke da alaƙa a cikin Applied Physics Letters a cikin 2024. Tare sun bayyana shi a fili: ainihin lahani na zobe mai da'ira shine hazo oxygen wanda ya ɗan yi ƙanƙanta. Halayensa guda uku duk "görünmez" ne ta yanayi:

• Ƙananan aiki na lantarki da sinadarai — ba irin hazo oxygen da kuke gani da sauri ba

• Matsayin lahani mara zurfi (0.42-0.46 eV, kuma ma fi zurfi bayan PDG)

• Görünmez a yanayin asali — wafer ɗin da aka girma bai nuna komai ba; dole ne ku kammala matakan zafi mai girma kamar yaduwa da annealing kafin ya bayyana

Wannan batu na ƙarshe shine inda injiniyoyi ke ƙonewa: mai "jinkirin haɓakawa" ne. A lokacin da kuka gani akan PL cell, asusun matakin wafer sun riga sun rufe.

Wannan Maƙiyi Ya Zaɓi Makaminsa — Kayan Aiki Na Yau da Kullum Ba Zai Iya Taɓa Shi Ba

Lahani na zobe mai da'ira suna juyar da yarjejeniya ta gargajiya cewa "idan za ku iya auna shi, maƙiyi ne."

Nuna makamai daban-daban ga wafer ɗaya tare da zoben da'ira:

Fassara zuwa harshen layin samarwa, jimla ɗaya ce: wannan maƙiyi yana zaɓar makaminsa. Kayan aiki na yau da kullun ba zai iya taɓa shi ba. A kan layi, kayan aikin da kawai ke kama shi kullum shine PL; don auna shi da gaske a dakin gwaje-gwaje kana buƙatar EBIC mai ƙarancin zafin jiki ko adon jan ƙarfe.

Wannan kuma shine dalilin da yasa injiniyoyi da yawa ke jin "bayanan duk sun wuce amma tantanin har yanzu yana mari ni a fuska." Bayanan ba karya ba ne. Makamin da ke hannun ba daidai ba ne.

Ma'aunin Fasaha

12 ppma: Layin Rayuwa ko Mutuwa ga Oxygen na Wafer N-Type

Tun da lahani na zobe mai da'irai shi ne haɗin iskar oxygen, tushen shi ne yawan iskar oxygen [Oᵢ] a cikin wafer.

Rahoton Li Guixiu ya zana layi mai haske sosai: [Oᵢ] > 12 ppma yana shiga yankin haɗin iskar oxygen mai yawan aiki (wanda tsofaffin injiniyoyi suka sani da "wafer mai duhu") ; [Oᵢ] < 12 ppma yana shiga yankin ƙananan OP, wanda shine zobe mai da'irai da muke magana akai a yau.

12 ppma shine layin rai da mutuwa ga iskar oxygen na wafer N-type (bisa ga ma'aunin SEMI M6 na kayan silicon, kusan 6×10¹⁷ cm⁻³). Bayanan masana'antu sun nuna fasahar tanderun lu'ulu'u guda ɗaya na yanzu tana iya kaiwa kusan 12.5 ppma; idan aka rage, yawan amfanin ƙasa yana raguwa sosai. Matsayin iskar oxygen da masana'antar wafer za ta iya kaiwa ya faɗi daidai kan layin da ke jawo lahani na zobe mai da'irai. Shi ya sa lahani na zobe mai da'irai ya zama ruwan dare a zamanin N-type.

Rahoton Li Guixiu ya ba da tabbataccen ƙarshe: a mafi munin yanayi, wafers da suka wuce 12 ppma [Oᵢ] na iya rasa har zuwa 4% cikakken ingancin tantanin halitta. "Mafi muni" a nan yana nufin matsanancin yanayi na oxygen wuce 12 ppma + canjin jawo-ƙima yana haifar da rarraba guraben da ba daidai ba + lahani na kai da wutsiya. Ba matsakaita ba ne; layi na gaske sau da yawa yana ganin asara a kan tsari na 0.4-1%.

Abin lura: binciken Li Guixiu na 2024 Applied Physics Letters ya nuna cewa ko a cikin wafers da oxygen ke ƙasa da 7×10¹⁷ cm⁻³ (~14 ppma), zanen concentric na iya haifar da har zuwa 0.86% cikakke asarar inganci. Wannan yana nufin haɗarin lahani yana nan har ma a ƙarƙashin 12 ppma. Rike 12 ppma shine layin ƙasa, ba layin gamawa ba.

Menene ma'anar 4% cikakke akan layin samarwa? Zuwa 2026, matsakaicin ingancin rukunin N-type cell mass-production ya bazu zuwa matakai: TOPCon a 25.6-26.2%, HJT a 26.0-26.5%, BC a 26.5-26.8%. Layin da ke aiki akai-akai yana kiyaye canjin matsakaicin motsi a cikin ±0.05% cikakke; da zarar matsakaicin batch ya faɗi fiye da 0.1%, ana dakatar da layin don bincike kuma a kira bita na inganci. Faɗuwar 4% mafi muni daga lahani na concentric ring yana daidai da tura dukan batch daga "babban mataki" zuwa "matakin rage daraja" ko ma "matakin sharar gida" — dukan tsarin fasaha na inganci yana tsallakewa.

Amma ga masana'antar wafer da cell, ainihin ciwo a cikin wannan littafin ba shine samar da wutar lantarki ba. Shi ne cewa wafers masu ƙarancin inganci ba za a iya siyar da su ba:

• Ƙarƙashin mafi ƙarancin ingancin abokin ciniki yana nufin mataccen kaya nan take: manyan abokan ciniki gabaɗaya suna saita mafi ƙarancin rukunin N-type cell a sama da 25.4% (wasu manyan abokan ciniki suna saita su sama da haka). Idan matsakaicin batch ya faɗi ƙasa da 25%, abokin ciniki ba zai karɓa ba kuma za a iya amfani da shi a ciki ko kuma a jefar da shi

• Siyar da aka rage darajar tana cin riba kai tsaye ta hanyar gibin farashin bin: kowane bin da ya ragu yana rage farashi da 'yan cents zuwa dime a kowace watt; a kan batch na ɗaruruwan MW, gibin na iya nufin miliyoyin zuwa miliyoyin goma a cikin ribar da ke ɓacewa

• Ƙwayoyin da aka samu a cikin samfurin suna nufin binciken batch gabaɗaya tare da haɗarin mayarwa: da zarar abokin ciniki ya sake duba EL/PL ya kama shi, sarkar lissafi ta biyo baya har zuwa masana'antar wafer

Wannan shine littafin da injiniya yake kallo da gaske — ba "yawan ƙarfin da tashar ke samarwa ya ragu" ba, amma "shin abokin ciniki zai karɓi wannan batch."

Me Yasa Wannan Matsala Ta Yi Muni a Zamanin N-Type

Haka nan ta kasance a zamanin P-type, amma ba ta da wannan matsala. Dalilai uku suna ƙara ta a zamanin N-type.

Dalili na ɗaya: kasafin zafi ya canza.

Tagar thermal cell N-type tsarin ne daban da P-type. P-type PERC phosphorus diffusion yana kaiwa 800-850°C — ba babba ba, amma hade da dogon zafin jiki annealing zai iya gyara ƙananan lahani. A hanyar N-TOPCon, boron diffusion peaks suna tashi zuwa 1000-1050°C — zafin jiki mafi girma, amma tare da lokutan zama da yanayi daban-daban, wanda maimakon haka yana "kunna" lahani masu alaƙa da oxygen. HJT ya fi tsanani: duk tsarin yana da ƙarancin zafin jiki (kusan 200°C), yana rasa kowane "high-temp anneal don narkar da lahani" bayan aiwatarwa. Da zarar gefen wafer yana da lahani na ɓoye, gefen cell ba shi da ƙarfi don ceto shi.

Dalili na biyu: manyan crucibles, munanan shigar da oxygen.

300mm babban diamita Cz + manyan crucibles + dogon lokacin jawo yana sa jimlar oxygen da ke narkewa daga crucible quartz ta tashi da yawa. A cikin tsarin ITRPV, layin manufa [Oᵢ] na wafer N-type yana ƙara tsauri kowace shekara.

Dalili na uku: ƙarancin gurɓatawa yana sa "tsofaffin makamai" su gaza.

Matsalolin haɗewar oxygen sun kasance suna da yawa saboda gurɓacewar ƙarfe na ƙara aikin sake haɗuwa. Takardar Wu Ruokai da sauransu ta 2025 a cikin Solar Energy Materials and Solar Cells (DOI: 10.1016/j.solmat.2025.113739) wannan an ƙididdige shi da EBIC:

• Haɗewar oxygen na asali (babu gurɓatawa) → bambancin EBIC ≈2% (kusan "ganuwa")

• Haɗewar oxygen bayan gurɓatar ƙarfe → bambancin EBIC ≈12% (aikin sake haɗuwa ya tashi 6×)

A cikin 'yan shekarun nan matakan gurɓatar ƙarfe sun ragu sosai, wanda ya sa haɗewar oxygen ta zama mafi "ganuwa." Wafers ɗin baƙin ciki da tsofaffin injiniyoyi ke iya gani akan PL ta gogewa sun ɓace, an maye gurbinsu da zobba masu haɗaka waɗanda ke buƙatar makamai na musamman don ganowa. Wannan shine rashin daidaituwa tsakanin "lissafin gurɓatar ƙarfe" da "lissafin oxygen."

Lura: cewa "ƙarancin gurɓatawa yana sa iskar oxygen ta zama ba a iya gani sosai" ba yana nufin "ƙarin gurɓatawa ya fi kyau" ba. Da zarar ƙarfe ya shiga, aikin haɗuwa da iskar oxygen ya ƙaru sau 6, yana haifar da lahani gabaɗaya. Rage gurɓatawa shine hanya madaidaiciya; kawai yana sa haɗarin "tsarkakken iskar oxygen" ya zama da wuya a gano shi da tsofaffin hanyoyi. Don haka magance gurɓatawa da sarrafa iskar oxygen duka ana buƙata kuma ba za su iya maye gurbin juna ba.

Fa'idodin Fasaha

Fassarar Hanyar: Ɗaya daga cikin motsi a cikin ƙimar ja, Ɗaya daga cikin zoben striations

Mafi kyawun ɓangaren rahoton Li Guixiu yana bayyana tsarin zoben concentric a sarari.

A cikin harshen layin samarwa: zoben concentric ba ya faruwa ne saboda yawan iskar oxygen ba, amma saboda rashin daidaituwa na radial na guraben [V].

Rahoton Li Guixiu yana amfani da bayanan simulation na CGSim don nuna cewa a ƙayyadadden ƙimar ja, yawan radial na guraben a cikin silikon ingot yana da "yawa a tsakiya, ƙasa a gefe," yana bambanta da fiye da oda ɗaya. Ma'aunin FTIR kuma ya tabbatar da cewa rarraba radial na [Oᵢ] da kansa yana da daidaito sosai (tsakiya 6.0×10¹⁷ cm⁻³ vs gefe 5.1×10¹⁷ cm⁻³). Don haka "zoben" yana zana ta hanyar guraben, ba ta iskar oxygen ba.

Ƙaddamar da haɗuwar oxygen tana buƙatar "[V] matsakaici": idan ya yi ƙasa da yawa ba zai iya haɗuwa ba, idan ya yi yawa kuma yana haifar da ramuka kai tsaye. Lokacin da saurin ja ya canza yayin ja, rarraba [V] a radial yana canzawa tare da shi, kuma wurin haɗuwar OP yana motsawa tare da radius — haka ake "zana" zoben striations.

Layi ɗaya: saurin ja tsayayye, lahani suna taruwa; saurin ja mai sauyawa, lahani suna zobe.

Yawancin injiniyoyin layi suna kuskuren tunanin cewa zoben concentric yana nufin "oxygen da yawa a gefe" kuma suna canza hanyar oxygen a yankin zafi — ba daidai ba. Zoben ana "zana" shi ne ta canjin vacancy, ba ta rashin daidaiton yawan oxygen ba.

Aikace-aikacen Samfur

Layukan Tsaro Uku: Yadda Layin Samarwa Yake Yaƙi da Wannan Yaƙin

Tare da bayyana tsarin, ga ɓangaren da injiniyoyi suka fi damuwa da shi: yadda ake yaƙi da wannan? An tsara su bisa jarin da aka zuba daga babba zuwa ƙarami, daga nesa zuwa kusa da layin, lahani na zoben concentric suna da layukan tsaro uku.

Layi na ɗaya: rage oxygen daga tushe (yanke mafi tsauri a girma kristal)

Aikin tsakiya: tura [Oᵢ] ƙasa da 12 ppma.

Babbar hujjar Li Guixiu ita ce bayanan MCz (magnetic Czochralski) da aka auna — tare da [Oᵢ] da aka sarrafa a 4 ppma (~2×10¹⁷ cm⁻³), duka wafer ɗin da aka girma da kuma wanda aka yi annealing a 750°C/16h + 1000°C/8-16h suna nuna [Oᵢ] radial gaba ɗaya daidai, kuma lahon zobe mai da'ira ya ɓace.

Kudin kuma a bayyane yake: MCz na buƙatar tsarin filin maganadisu, yana ƙara farashin kera ingot. Wannan kariyar ta dace da manyan masu yin wafer akan samfuran N-type masu daraja; ba kowane layi zai iya ɗauka ba.

Layi na biyu: daidaita tsari (aikin yau da kullun a girma crystal)

Ko da ba tare da MCz ba, akwai abubuwa da yawa da za a yi:

• Sarrafa canjin saurin ja — mabuɗin shine "tsayayye," ba "sauri" ba. Gara a sadaukar da ɗan ingancin ja fiye da barin [V] ya canza

• Ja da aka yi da nitrogen — bayanan da aka auna daga rahoton Wang Pengfei na Jinko 2026: tsawon rayuwar mai ɗaukar ƙarami ya haura 7%, ingancin tantanin ya haura 0.01%. Kwayoyin nitrogen suna ɗaure guraben da suka wuce, suna hana samuwar rami da haɓakar oxygen precipitate, kuma daga baya matakan zafi sun sake sakin nitrogen

• Rage da tsayawa a taga 850-650°C — yayin sanyaya ingot, oxygen yana taruwa da sauri tare da taimakon vacancy; wannan taga zafin jiki shine "defect incubator," don haka ku wuce ta cikinsa da sauri gwargwadon iko

Layi na uku: duban wafer mai shigowa (kofar karshe ta masana'antar cell)

Yadda ake duban wafer mai shigowa? Wang Pengfei ya ba da ma'auni guda biyu masu wuya:

• Yawan ƙananan lahani < 40 a kowace mm²

• Shaƙar oxygen precipitate < 0.5 (FTIR kololuwar shaƙa a 1230 cm⁻¹)

Don hanyoyin HJT, ƙara biyu:

• Hoton PL don dubawa don "yankuna masu duhu masu kama da swirl" — kawai shaidar da ake gani na lahani na zobe mai da'ira a gefen wafer

• Fi son mataki biyu na phosphorus pre-gettering (2nd PDG) fiye da mataki daya — takardar Wu Ruokai ta tabbatar cewa ko bayan PDG, PCE na wafer mai lahani yana 0.4% cikakke ƙasa da wafer na yau da kullun (mai lahani 24.68% vs na yau da kullun 25.08%, bayanan lab). Ko da yake wannan ƙananan bayanan cell ne na lab, girman yana aiki a matsayin tunani: 0.4% cikakke akan layin taro yana nufin dukan batch ya faɗi bins biyu, yana rushe rarraba bin samfurin kuma yana haifar da matsalolin bayarwa-oda — asara mai zafi fiye da littafin "nawa wutar"

Idan tsarin tantanin halitta ya ba da dama, shigar da anneal na "defect-dissolving" kafin boron diffusion (1100°C fast ramp, riƙe 10-30 mintuna, fast cool) yana ba da kusan 1000 PL brightness gain a cewar rahoton Wang Pengfei, tare da kiyasin 0.02-0.03% cell gain. Wannan shine ƙaramin canji da za ku iya saka a cikin layin da ke akwai.

Abubuwa Uku da Rahoton da Takardun Ba Su Faɗa Muku Ba

Don rufe ɓarnawar fasaha, dole ne a bayyana iyakokin takardun kuma.

Na farko, "cin 4% inganci" shine mafi munin yanayi bayan ketare layin. 12 ppma layin gargadi ne, ba "ketare shi kuma tabbas za ku rasa 4%" ba. Bayan oxygen ya ketare wannan layin, idan canjin vacancy ya taru, asarar tana iyo tsakanin 0 da 4% cikakke; 4% shine rufin, kuma takardar Wu Ruokai ta nuna ainihin ragowar wafers marasa lahani da na yau da kullun shine 0.4% cikakke. Matakan bayanai guda uku suna da alaƙa kamar haka: 4% shine iyakar matsananciyar layin ketare + canjin guraben aiki + tara kai da wutsiya; 0.86% shine ma'aunin dakin gwaje-gwaje lokacin da iskar oxygen ta ɗan fi 12 ppma (Li Guixiu APL 2024); 0.4% shine ragowar bayan PDG (Wu Ruokai 2025). Idan ka daɗe a kan layi kuma abin da ya tara ya fi yawa, za ka kusanci wannan iyakar 4%. 12 ppma tana riƙe da layin ƙasa na "kar ka shiga yankin aikin sake haɗuwa mai yawa."

Na biyu, lissafin kuɗin MCz bai cika dalla-dalla ba. Rahotannin ilimi suna warware "za a iya yi"; injiniyoyi har yanzu suna lissafin "ko yana da daraja." A wane girman layi ne MCz ke daidaita? Wannan ya dogara da farashin N-type cell premium — a halin yanzu layukan samfurori na HJT na iya tallafawa, N-TOPCon na yau da kullun har yanzu yana da wahala.

Na uku, haɗin nitrogen doping da HJT ba a rufe shi sosai a cikin littattafan kimiyya. Shin nitrogen zai yi hulɗa da hydrogen a cikin tsarin HJT? Littattafan da ake da su galibi suna tabbatarwa akan hanyar N-TOPCon; bayanan hanyar HJT har yanzu ba su isa ba.

Takaitaccen Layi Daya

Zamanin P-type ya kasance game da "kawar da BO biyu"; zamanin N-type shine game da "kulle abubuwan da ke haifar da oxygen." Abokin hamayya ya canza kamanni, don haka makaman injiniya su ma dole su canza — Hoton PL yana kallon wurin, EBIC mai ƙarancin zafin jiki yana ƙididdigewa, [Oᵢ] < 12 ppma yana riƙe layin mutuwa, saurin ja yana tsayawa, PDG mataki biyu yana goyon baya.

Mai kashewa marar ganuwa ba abin tsoro ba ne. Abin tsoro shine kawo makaman yau da kullum don yaƙar shi.

Ra'ayin Ooitech

Abin da ya ba ni mamaki a nan shi ne yadda makomar layin N-type ke yanke shawara a sama, a lokacin girma na crystal, tun kafin kowane kayan aikin tantanin halitta ya ga wafer. Zoben da ke kewaye da saurin ja mai jujjuyawa ba za a iya gyara shi gaba ɗaya a ƙasa ba, don haka layin tantanin halitta yana gadar matsalar da bai yi ba. A kan layukan samar da mu na module muna ganin gefen wannan — kyawawan wafers da aka ɓata ta hanyar karkatar da tsari, ko waɗanda aka cece ta hanyar tantancewa sosai — wanda shine dalilin da ya sa horon hoton PL yake da mahimmanci a gefen module kamar yadda yake a binciken shigowa. Idan kana son ganin yadda wannan ke aiki a kan layin atomatik na gaske, tashar mu ta YouTube a www.youtube.com/ooitech tana da hotunan masana'anta da yawa da suka cancanci kallo. Babban layi: riƙe 12 ppma, ci gaba da ja a hankali, kuma ka amince da PL fiye da takardu.

Nassoshi

Li Guixiu (Jami'ar Zhejiang). Matsalolin Zobe Mai Ciki a cikin N-type Photovoltaic Czochralski Single-Crystal Silicon. 21st CSPV, 2025-11-27

Li G, Yuan S, Zhou S, et al. Rarrabuwar layuka a cikin n-type Czochralski silicon solar cells. Applied Physics Letters, 2024, 125(25)

Wang Pengfei (Jinko Solar). Halayen Ingancin PV Single-Crystal Silicon da Magance Lalacewa. 2026

R. Wu, et al. Tasirin phosphorus diffusion pre-gettering akan kaddarorin lantarki na lahani masu alaka da oxygen a cikin n-type crystalline silicon heterojunction cells. Solar Energy Materials and Solar Cells 290 (2025) 113739. DOI: 10.1016/j.solmat.2025.113739

B. Vicari Stefani. Binciken Lalacewar Jiki a cikin p-type Silicon Wafers da Solar Cells (PhD Thesis), 2022