SiNx Ya Yi Siriri Sama da Azurfa Ta Huda Ta Poly Layer, Ya Yi Kauri Sama da Juriya Ta Tsalle 600x: ISFH Ta Nuna Magani
Gabatarwar Samfur
Duk wanda ke gudanar da layin aikin TOPCon ya fuskanci wannan matsala. Idan ka rufe SiNx da siriri sosai, kana damuwa cewa tafarnuwa ta azurfa ta ƙone ta cikin layin passivation, tana jawo Voc ƙasa. Idan ka rufe shi da kauri sosai, juriyar lamba ta tashi, kuma FF ba zai iya tsayawa ba. Siriri yana tsoratar da kai, kauri ma yana tsoratar da kai — to, yaya kauri ne "daidai"?
A cikin 2022, ƙungiyar Min Byungsul a ISFH (Cibiyar Binciken Makamashin Rana ta Hamelin, Jamus) ta buga wani bincike a cikin AIP Conference Proceedings wanda ya warware wannan matsala. Sun yi amfani da POLO passivating contacts — sunan ilimi wanda masana'antu ke kira TOPCon, ainihin tsari ne na bakin ciki oxide plus doped polysilicon poly-Si/SiOx — don ware abin da ke faruwa da gaske.
Babban abin da aka fahimta ba shi da rikitarwa: kaurin SiNx da zafin wuta suna da alaƙa. Canza kauri sai ka daidaita zafin. Matsar da ɗaya ba tare da matsar da ɗayan ba ko Voc ya faɗi ko FF ya rushe.
Ma'aunin Fasaha
Yadda aka kafa gwajin
ISFH ta yi amfani da p-type CZ wafers, tare da n⁺ POLO contact a bayan tantanin (tunnel oxide plus phosphorus-doped polysilicon).
Abubuwa biyu masu mahimmanci:
Kaurin rufin SiNx na baya — daga 40nm zuwa 80nm
Matsakaicin zafin wuta — an daidaita tsakanin 790°C da 810°C
Sai suka auna abubuwa biyu: resistivity na lamba ρc (ta hanyar TLM) da sigogin IV na tantanin.
A baya mun kalli takardar JA Solar ta 2016 kan yadda sinadaran abun da ke ciki (rabon Si/N) na gaba fim ɗin SiNx anti-reflection yake shafar lambar farar azurfa. Wannan aikin ISFH na 2022 yana game da yadda kaurin jiki na baya rufin SiNx yake shafar lambar farar azurfa. Haɗa su biyun ka rufe dukkan bangarori biyu — "sinadaran abun da ke ciki" da "kaurin jiki," fim ɗin gaba da fim ɗin baya.
Dukkan samfuran an harba su a 800°C, kaurin SiNx na baya kawai aka bambanta
| Kaurin SiNx | Matsakaicin ρc (800°C) | Matsayi |
|---|---|---|
| 40nm | ~1 mΩ·cm² | Kadan sosai |
| 50nm | ~1.5 mΩ·cm² | Fara tashi |
| 60nm | ~7 mΩ·cm² | Tashi a fili |
| 70nm | ~30-40 mΩ·cm² | Yankin canji, hawa mai tsauri |
| 80nm | ~600 mΩ·cm² | Kusan sau 600 mafi girma fiye da a 40nm |
Binciken zafin harbi akan samfurori 55nm da 60nm
| Yanayi | Matsakaicin ρc |
|---|---|
| 55nm SiNx + 800°C | 3.2 mΩ·cm² |
| 60nm SiNx + 805°C | 2.8 mΩ·cm² |
| 60nm SiNx + 810°C | 2.0 mΩ·cm² |
Fa'idodin Fasaha
Binciken farko: yayi kauri sosai kuma manna ba zai iya harbawa ta ciki ba
Duk samfurori an harba su a 800°C kololuwa, canza kawai kaurin SiNx na baya. Tsarin a bayyane yake daga teburin da ke sama — adadin SiNx da manna zai iya ƙonewa yayin harbawa yana da iyaka. Ketare wannan iyaka kuma manna ba zai taɓa isa ga polysilicon da ke ƙasa ba, don haka juriyar lamba ta tashi.
Hotunan SEM suna ba da shaida kai tsaye:
40nm SiNx: manna ya ƙone gaba ɗaya ta cikin SiNx da polysilicon, ya bar yalwa na ramukan ƙazamin micron akan poly. An cire polysilicon gaba ɗaya a wurin — kyakkyawar lamba, amma layin kariya ya lalace.
80nm SiNx: kawai ƙananan ramuka masu ƙanƙanta, babu wuraren da aka cire poly gaba ɗaya — kariya ta riƙe, amma juriyar lamba ta kusan sau 600 (kusan oda 2.8), kuma FF ta lalace.
Ƙarshen ISFH a bayyane yake: akwai taga SiNx mafi kyau — tsakanin 50 zuwa 60nm. Da yawa sirara, manna ya huda kariya kuma Voc ya ragu. Da yawa kauri, manna ba zai iya shiga ba kuma juriyar lamba ta tashi.
Bincike na biyu: kauri da zafin jiki suna haɗe
ISFH bai tsaya a "50-60nm shine mafi kyau." ba. Sun yi wata tambaya mai amfani ta shagon: idan kaurin SiNx ya canza, shin zafin harba yana buƙatar canzawa ma?
Sun zaɓi 55nm da 60nm ƙungiyoyi kuma suka gudanar da binciken zafin jiki daga 790°C zuwa 810°C.
Sakamakon yana da tsabta sosai:
55nm SiNx: FF ya kai kololuwa a 800°C, mafi kyawun inganci a can. Ka yi ƙasa kuma haɗin bai isa ba; ka yi sama kuma passivation ta fara wahala.
60nm SiNx: FF ya kai kololuwa a 805-810°C. Domin SiNx ya fi kauri, yana buƙatar zafi mafi girma don manna ya harba ta.
A cikin kalmomi masu sauƙi: a ƙarƙashin waɗannan yanayin gwaji, tafiya daga 55nm zuwa 60nm yana canza mafi kyawun zafin harba da kusan 5-10°C. Wannan gangare kawai tunani ne ga tsarin manna guda ɗaya — canza manna kuma kana buƙatar sake daidaitawa.
Bayanan juriyar tuntuɓar sun goyi bayan hakan: yawan zafin jiki, mafi kyawun tuntuɓa — muddin ba ka ketare layin da za ka fara ƙonewa ta cikin passivation ba.
Hanyar: girman ramin etch shine mabuɗin
ISFH ta yi amfani da SEM don tsara ma'auni mai bayyananne:
Ramin da ya fi 1μm diamita: poly an cire gaba ɗaya, passivation ta lalace → Voc ya faɗi
Ramin da bai kai 1μm diamita ba: poly ba a cire gaba ɗaya ba, passivation ta tsaya → juriyar tuntuɓa ta faɗi, Voc bai canza ba
ISFH ta faɗi kai tsaye: "wasu adadin ƙananan ramukan etch ya zama dole don samar da kyakkyawar tuntuɓa. Ramin etch da ke ƙasa da 1μm diamita da alama ba su da tasiri akan ingancin passivation."
Ma'aunin layi: ramukan etch ba su fi kyau da ƙanƙanta ba, kuma ba su fi kyau da yawa ba — manufar ita ce ƙananan girma, matsakaicin rarraba. Idan ka ga ramuka masu yawa >1μm a ƙarƙashin microscope, zafin jiki ya yi yawa ko SiNx ya yi bakin ciki, kuma passivation tana ɗaukar lalacewa.
Aikace-aikacen Samfur
Menene layin samarwa zai iya amfani da shi a zahiri?
1. Kauri na SiNx ba shi da kyau idan ya yi siriri, kuma ba shi da kyau idan ya yi kauri. A ƙasa da 40nm, manna yana ƙonewa ta cikin rufin kuma Voc yana raguwa; sama da 80nm, manna ba zai iya ƙonewa ba kuma juriyar haɗuwa ta tashi kusan sau 600.
2. Kauri da zafin jiki suna haɗe. Canza kauri na SiNx kuma zafin ƙonewa dole ne ya biyo baya. Bayanan ISFH suna ba da misali — a ƙarƙashin waɗannan yanayi, kowane ƙarin 5nm na SiNx yana motsa mafi girman zafin jiki sama da kusan 5-10°C — amma a sake daidaita bayan canza manna.
3. Ramukan etching alama ce ta "taga". Dubi girman rami da yawa ta hanyar SEM kuma za ku iya tantance ko haɗin kauri-zafin jiki na yanzu yana cikin taga. Yawancin ramuka >1μm → zafi da yawa ko fim ya yi siriri; kusan babu ramuka → sanyi da yawa ko fim ya yi kauri, haɗuwa na iya zama matsala.
4. Kaurin fim na baya shima yana sarrafa yawan kyau, da zaɓin manna. Abubuwa uku da ke sama duk sun shafi yadda kauri yake shafar juriyar tuntuɓar da FF ta hanyar wutar manna ta wuce ko a'a. Amma a kan layi, kaurin SiNx na baya yana sarrafa fiye da aikin lantarki.
A cikin samarwa da yawa na gaske, SiNx na baya yawanci ana sarrafa shi a cikin 70-85nm kewayon — mai kauri fiye da 50-60nm "mafi kyawun tuntuɓar" a cikin takardar ISFH. Dalili mai sauƙi: takardar ta auna mafi kyawun tuntuɓar tsantsa don tsarinta na POLO da wani manna na musamman, yayin da layin samarwa dole ne ya daidaita passivation, tuntuɓar da daidaiton launi gaba ɗaya, kuma ya zaɓi kewayon mai kauri, mafi kwanciyar hankali. Mafi mahimmanci, manna layin kasuwanci suna amfani da tsarin gilashin-frit daban da na manna lab na ISFH, don haka taga kaurin SiNx da za a iya ƙonewa ta shima ya bambanta.
Canza kauri kuma ma'anar refractive ta canza, kuma launin tsangwama na fim ɗin yana canzawa da shi. Da kauri sosai ko kauri sosai kuma wafers suna nuna bambancin launi, rashin launi da makamantansu na rage kyawu waɗanda kai tsaye ke yanke yawan kyawu. Wannan kuma yana sanya buƙatu mai ƙarfi ga mai yin manna: manna dole ne ya dace da taga aikin fim na baya, ba tilasta fim ɗin baya ya daidaita da wani manna na musamman ba. Kauri da zafin jiki dole ne su daidaita, kuma manna da kaurin fim dole ne su daidaita — layin tsari ne, ba gyara guda ɗaya ba.
Abubuwa uku da takardar ba ta faɗi ba
Dangantaka tsakanin POLO da TOPCon. POLO contact da ISFH ta yi amfani da shi ainihin siririn oxide ne mai ɗauke da polysilicon (poly-Si/SiOx), daidai da tsarin baya na TOPCon na yau, don haka sakamakon yana aiki kai tsaye. POLO shine sunan ilimi da ISFH ta gabatar; TOPCon shine kalmar masana'antu; tsari ɗaya ne a zuciya.
Samfurin manna yana shafar zurfin shiga. Manna daban-daban suna da abubuwan haɗin gilashin frit daban-daban kuma suna iya ƙone ta cikin kaurin SiNx daban-daban. Kaurin 50-60nm na ISFH ya dogara da wani manna na musamman — canza manna kuma kana iya buƙatar sake daidaitawa.
Doguwar aminci ba a rufe ba. Shin ƙananan ramukan tsatsa za su girma zuwa manya bayan shekaru 25 na tsufa a waje? Shin za a iya ƙara lalacewar mu'amala a ƙarƙashin zafi da danshi? Takardar ba ta amsa ba.
Karanta shi tare da JA Solar 2016
| Girma | JA Solar 2016 | ISFH 2022 |
|---|---|---|
| Aikace-aikace | Fim ɗin gaban SiNx anti-reflection (ARC) | Fim ɗin bayan SiNx capping |
| Mai da hankali | Abubuwan sinadaran SiNx (rabon Si/N) | Kauri na zahiri na SiNx |
| Mahimmin canji | Rabon gas SiH₄/NH₃ | Kaurin SiNx + zafin wuta |
| Yanayin gazawa | Rashin daidaiton rabon Si/N → rashin daidaiton dankon frit → babban juriyar tuntuɓa | Kauri mara daidai → ƙonewa ko rashin ƙonewa |
| Hanyar gyarawa | Daidaita rabon gas zuwa mafi kyawun taga | Haɗa kauri da zafin jiki |
| Hanyar haɗin gwiwa | Halin amsawar Frit-SiNx yana ƙayyade ingancin tuntuɓa | Zurfin shigar Frit-SiNx yana ƙayyade ingancin tuntuɓa |
Sanya takardun biyu gefe da gefe kuma za ku sami cikakken hoto na tsarin fim ɗin gaba da baya: abubuwan sinadaran suna ƙayyade ko za ku iya tuntuɓa da kyau, kauri na zahiri yana ƙayyade ko kuna cutar da abin da ke ƙasa yayin tuntuɓa.
Nudge the coating Si/N ratio and Rs spikes, FF collapses, efficiency craters
A reminder for the line: don't only stare at poly when hunting for efficiency loss
With both papers done, back to our own line. When chasing efficiency loss, an engineer's reflex is to first check rear poly thickness, doping level, tunnel oxide thickness — their impact on FF and Voc is well understood and these are standard check items. But the rear SiNx capping layer often gets waved off as a "passivation/cosmetic layer," and few people think of it in terms of contact resistance.
The value of this ISFH paper is exactly that it drags this overlooked variable back onto the table: wrong back-film thickness, paste doesn't fire through or burns through, and FF collapses all the same. Next time you hit a "poly parameters untouched, yet FF mysteriously dropped" situation, don't just circle around the poly — go back and check whether back-film thickness and firing temperature still pair.
Abin lura: Gwajin ISFH ya dogara ne akan harba na al'ada. Fasahar LECO da aka fi amfani da ita a kan layukan na iya inganta hulɗa ta hanyar matakin laser/na yanzu na gaba, wanda zuwa wani mataki yana rage hankali ga haɗin harba-zazzabi-kauri — amma kauri na fim ɗin baya har yanzu shine taga tushe kuma ba za a iya watsi da shi ba.
Ra'ayin Ooitech
Muna ganin abu ɗaya a kowane layin TOPCon da muke kaddamarwa — rufin SiNx na baya ana ɗaukarsa azaman fim ɗin launi kawai, sannan FF yana zamewa a hankali ba tare da kowa ya duba haɗin kauri-zazzabi ba. Bayanan ISFH sun yi daidai da abin da ke tura mutane zuwa LECO, tunda raba samuwar hulɗa daga matakin harba yana ba da riba ta gaske lokacin da sinadarin frit na manna da taga fim ɗin baya ba su yarda sosai ba. Idan kana son ganin yadda waɗannan matakan ke aiki a kan layin module na gaske — rufi, harba, zaren da duka — tashar Ooitech YouTube a www.youtube.com/ooitech ya cancanci bi. Kuma ka tuna wannan nazari ne a matakin tantanin halitta; layin module yana gadon waɗannan tantanin halitta amma makomar hulɗa ta riga ta rufe a sama.
Manazarta
Min B. et al., AIP Conf. Proc. 2487, 020014 (2022) (DOI: 10.1063/5.0089239)
Chen X.Y. et al., Solar Energy 126 (2016) 105–110 (DOI: 10.1016/j.solener.2016.01.001)
