Iyini i-chip ye-LED? Ngakho yiziphi izici zayo? Ukwenziwa kwama-chips e-LED kuhloswe kakhulu ukukhiqiza ama-electrode othintana naye we-ohmic asebenzayo futhi anokwethenjelwa, angahlangabezana nokwehla kwamandla kagesi amancane phakathi kwezinto zokuxhumana futhi ahlinzeke ngamaphedi okuthengisa, kuyilapho ekhipha ukukhanya okuningi ngangokunokwenzeka. Inqubo yokudlulisa ifilimu ngokuvamile isebenzisa indlela yokuhwamuka kwe-vacuum. Ngaphansi kwe-vacuum ephezulu ye-4Pa, i-material incibilika ngokushisisa kokumelana noma indlela yokushisa ye-electron beam bombardment, futhi i-BZX79C18 iguqulwa ibe umhwamuko wensimbi futhi ifakwe phezu kwempahla ye-semiconductor ngaphansi kwengcindezi ephansi.
Izinsimbi ezisetshenziswa kakhulu zohlobo lwe-P zihlanganisa ama-alloys afana ne-AuBe ne-AuZn, kuyilapho insimbi yokuxhumana ye-N-side ngokuvamile yenziwe nge-AuGeNi alloy. Isendlalelo se-alloy esakhiwe ngemva kokumbozwa sidinga futhi ukuveza indawo ekhipha ukukhanya ngangokunokwenzeka ngobuchwepheshe be-photolithography, ukuze ungqimba olusele lwe-alloy lukwazi ukuhlangabezana nezidingo zama-electrode othintana nama-ohmic aphansi asebenzayo kanye nama-solder wire pads. Ngemuva kokuthi inqubo ye-photolithography isiqediwe, inqubo ye-alloying nayo yenziwa, ngokuvamile ngaphansi kokuvikelwa kwe-H2 noma i-N2. Isikhathi kanye nezinga lokushisa kwe-alloying ngokuvamile kunqunywa izici ezifana nezici zezinto zokwakha ze-semiconductor kanye nesimo somlilo we-alloy. Vele, uma inqubo ye-electrode yama-chips aluhlaza okwesibhakabhaka iyinkimbinkimbi, ukukhula kwefilimu ye-passivation kanye nezinqubo zokufaka i-plasma kufanele zengezwe.

Enqubweni yokukhiqiza ama-chips e-LED, yiziphi izinqubo ezinomthelela omkhulu ekusebenzeni kwawo kwe-optoelectronic?
Ngokuvamile, ngemva kokuphothulwa kokukhiqizwa kwe-LED epitaxial, izakhiwo zayo eziyinhloko zikagesi seziqediwe, futhi ukukhiqizwa kwama-chip akushintshi imvelo yayo eyinhloko. Kodwa-ke, izimo ezingalungile phakathi nezinqubo zokuhlanganisa kanye ne-alloying zingabangela imingcele engalungile kagesi. Isibonelo, amazinga okushisa aphansi noma aphezulu e-alloying angabangela ukuthintana kwe-ohmic okubi, okuyisizathu esiyinhloko sokwehla kwe-VF ephezulu ye-voltage eya phambili ekukhiqizeni ama-chip. Ngemva kokusika, ukwenza ezinye izinqubo zokugqwala emaphethelweni e-chip kungaba usizo ekuthuthukiseni ukuvuza okuphambene kwe-chip. Lokhu kungenxa yokuthi ngemva kokusika ngensimbi yesondo lokugaya idayimane, kuzoba nenani elikhulu lempushana esele emaphethelweni e-chip. Uma lezi zinhlayiya zinamathela ekuhlanganeni kwe-PN kwe-chip ye-LED, zizobangela ukuvuza kukagesi ngisho nokuphuka. Ngaphezu kwalokho, uma i-photoresist ebusweni be-chip ingahlutshiwe ngokuhlanzekile, izodala ubunzima kanye nokuhlanganisa okubonakalayo kwemigqa ye-solder yangaphambili. Uma ingemuva, izophinde ibangele ukwehla komfutho ophezulu. Ngesikhathi senqubo yokukhiqiza ama-chip, izindlela ezinjengokuhwashaza komhlaba kanye nokusika ezakhiweni ze-trapezoidal ezihlanekezelwe zingakhuphula amandla okukhanya.

Kungani ama-chips e-LED ahlukaniswa ngamasayizi ahlukene? Iyini imiphumela yosayizi ekusebenzeni kwe-photoelectric ye-LED?
Usayizi wama-chips e-LED ungahlukaniswa ube ama-chips anamandla aphansi, ama-chips amandla aphakathi nendawo, nama-chips anamandla amakhulu ngokuya ngamandla awo. Ngokwezidingo zamakhasimende, ingahlukaniswa ngezigaba ezifana neleveli yeshubhu eyodwa, ileveli yedijithali, ileveli ye-matrix yamachashazi, nokukhanya kokuhlobisa. Ngokuqondene nosayizi othize we-chip, kuncike ezingeni langempela lokukhiqiza labakhiqizi abahlukene be-chip futhi azikho izidingo ezithile. Inqobo nje uma inqubo isezingeni elifanele, ama-chips amancane angakhuphula ukuphuma kweyunithi futhi anciphise izindleko, futhi ukusebenza kwe-optoelectronic ngeke kube nezinguquko ezibalulekile. I-current esetshenziswa i-chip empeleni ihlobene nokuminyana kwamanje okugeleza kuyo. I-chip encane isebenzisa i-current encane, kuyilapho i-chip enkulu isebenzisa amandla amaningi. Ukuminyana kweyunithi yabo kwamanje kuyafana. Uma kucatshangelwa ukuthi ukuchithwa kokushisa kuyindaba eyinhloko ngaphansi kwamandla aphezulu, ukusebenza kahle kwawo okukhanyayo kuphansi kunalokho okungaphansi kwamandla aphansi. Ngakolunye uhlangothi, njengoba indawo ikhula, ukumelana komzimba we-chip kuzokwehla, okuholela ekunciphiseni kwe-voltage conduction phambili.

Iyiphi indawo ejwayelekile yama-chips anamandla aphezulu e-LED? Kungani?
Ama-chips anamandla amakhulu e-LED asetshenziselwa ukukhanya okumhlophe ngokuvamile atholakala emakethe cishe ngo-40mil, futhi ukusetshenziswa kwamandla kwama-chips anamandla ngokuvamile kubhekisela kumandla kagesi angaphezu kuka-1W. Ngenxa yokuthi ukusebenza kahle kwe-quantum ngokuvamile kungaphansi kuka-20%, amandla kagesi amaningi aguqulwa abe amandla okushisa, ngakho-ke ukuchithwa kokushisa kwama-chips anamandla kubaluleke kakhulu futhi kudinga ama-chips ukuba abe nendawo enkulu.

Yiziphi izidingo ezihlukene zenqubo ye-chip kanye nezisetshenziswa zokucubungula zokukhiqiza izinto ze-GaN epitaxial uma kuqhathaniswa ne-GaP, i-GaAs, ne-InGaAlP? Kungani?
Ama-substrates ama-LED ajwayelekile abomvu naphuzi chips kanye nokukhanya okuphezulu kwe-quaternary abomvu naphuzi ama-chips enziwe ngezinto ezihlanganisiwe ze-semiconductor ezifana ne-GaP nama-GaAs, futhi ngokuvamile angenziwa abe ama-substrates ohlobo lwe-N. Inqubo emanzi isetshenziselwa i-photolithography, bese izindwani zamasondo okugaya idayimane zisetshenziselwa ukusika ama-chips. I-chip eluhlaza okwesibhakabhaka eyenziwe ngezinto ze-GaN isebenzisa i-sapphire substrate. Ngenxa yemvelo yokuvikela ye-sapphire substrate, ayikwazi ukusetshenziswa njenge-electrode eyodwa ye-LED. Ngakho-ke, womabili ama-electrode e-P/N kufanele enziwe ngesikhathi esisodwa endaweni ye-epitaxial ngenqubo yokuqopha okomile, futhi ezinye izinqubo zokudlula kufanele zenziwe. Ngenxa yokuqina kwesafire, kunzima ukuyisika ibe ama-chips ngensimbi yesondo lokugaya idayimane. Inqubo yayo yokukhiqiza ngokuvamile iyinkimbinkimbi futhi iyinkimbinkimbi kunama-LED enziwe ngezinto ze-GaP noma ze-GaAs.

Yiziphi ukwakheka nezici ze-chip "electrode esobala"?
I-electrode ebizwa ngokuthi i-transparent idinga ukuba iqhube futhi ibonakale. Le nto manje isetshenziswa kabanzi ezinqubweni zokukhiqiza i-crystal ewuketshezi, futhi igama layo yi-indium tin oxide, efushanisiwe njenge-ITO, kodwa ayikwazi ukusetshenziswa njenge-solder pad. Uma wenza, qala wenze i-electrode ye-ohmic ebusweni be-chip, bese uvala indawo engaphezulu ngongqimba lwe-ITO bese unamathisela ungqimba lwe-solder pad endaweni ye-ITO. Ngale ndlela, okwamanje okwehla kumthofu kusatshalaliswa ngokulinganayo ku-electrode yokuxhumana ye-ohmic ngayinye ngesendlalelo se-ITO. Ngesikhathi esifanayo, i-ITO, ngenxa yokuthi inkomba yayo ye-refractive iphakathi kwalokho yomoya nezinto ze-epitaxial, ingakhuphula i-engeli yokukhishwa kokukhanya kanye nokugeleza okukhanyayo.

Kuyini ukuthuthukiswa okujwayelekile kobuchwepheshe be-chip bokukhanyisa kwe-semiconductor?
Ngokuthuthukiswa kobuchwepheshe be-semiconductor LED, ukusetshenziswa kwayo emkhakheni wokukhanyisa kuyanda, ikakhulukazi ukuvela kwe-LED emhlophe, eye yaba isihloko esishisayo ekukhanyeni kwe-semiconductor. Kodwa-ke, ubuchwepheshe bokhiye be-chip kanye nokupakisha busadinga ukuthuthukiswa, futhi ngokuya ngama-chips, sidinga ukuthuthukisa amandla aphezulu, ukusebenza kahle kokukhanya okuphezulu, nokunciphisa ukumelana nokushisa. Ukwenyuka kwamandla kusho ukwanda kwamandla asetshenziswa yi-chip, futhi indlela eqondile iwukwandisa usayizi we-chip. Ama-chips asetshenziswa kakhulu amandla aphezulu acishe abe ngu-1mm × 1mm, anamandla angu-350mA. Ngenxa yokwanda kokusetshenziswa kwamanje, ukuchithwa kokushisa sekuyinkinga evelele, futhi manje le nkinga isixazululwe ngokuyisisekelo ngokusebenzisa indlela yokuguqulwa kwe-chip. Ngokuthuthukiswa kobuchwepheshe be-LED, ukusetshenziswa kwayo emkhakheni wokukhanyisa kuzobhekana namathuba nezinselele ezingakaze zibonwe ngaphambili.

Kuyini “i-flip chip”? Sinjani isakhiwo sawo? Yiziphi izinzuzo zayo?
I-Blue LED ivamise ukusebenzisa i-Al2O3 substrate, enobunzima obuphezulu, i-thermal ephansi kanye ne-electrical conductivity. Uma isakhiwo esihle sisetshenziswa, sizoletha izinkinga eziphikisana ne-static ngakolunye uhlangothi, futhi ngakolunye uhlangothi, ukuchithwa kokushisa kuzoba yinkinga enkulu ngaphansi kwezimo eziphezulu zamanje. Phakathi naleso sikhathi, ngenxa ye-electrode enhle ebheke phezulu, ingxenye yokukhanya izovinjelwa, okuholela ekunciphiseni kokusebenza kahle okukhanyayo. I-LED enamandla aluhlaza okwesibhakabhaka ingafinyelela ukukhanya okuphumayo okusebenzayo ngobuchwepheshe bokuguqulwa kwe-chip kunobuchwepheshe bokupakisha bendabuko.
Indlela yesakhiwo ehlanekezelwe eyinhloko manje iwukuqala ngokulungisa ama-chips e-LED anosayizi omkhulu aluhlaza anama-electrode e-eutectic soldering afanelekile, futhi ngesikhathi esifanayo ulungise i-silicon substrate enkulu kune-chip ye-LED eluhlaza okwesibhakabhaka, bese wenza ungqimba lwegolide olubambayo bese ukhipha ucingo. ungqimba (i-ultrasonic wire ball solder joint) ye-eutectic soldering kuso. Ngemuva kwalokho, i-chip ye-LED enamandla amakhulu aluhlaza idayiswa ku-silicon substrate kusetshenziswa imishini ye-eutectic soldering.
Isici salesi sakhiwo ukuthi ungqimba lwe-epitaxial luthinta ngokuqondile i-silicon substrate, futhi ukumelana nokushisa kwe-silicon substrate kuphansi kakhulu kune-sapphire substrate, ngakho-ke inkinga yokushisa ukushisa ixazululwa kahle. Ngenxa ye-sapphire substrate ehlanekezelwe ebheke phezulu, iba indawo ekhipha ukukhanya, futhi isafire ibonakalisa ngale, ngaleyo ndlela kuxazululwe inkinga yokukhishwa kokukhanya. Okungenhla ulwazi olufanele lobuchwepheshe be-LED. Sikholelwa ukuthi ngokuthuthukiswa kwesayensi nobuchwepheshe, izibani ze-LED zesikhathi esizayo zizosebenza kahle kakhulu futhi impilo yazo yesevisi izothuthukiswa kakhulu, okusilethela ukunethezeka okukhulu.