Ka'idojin Fasaha da Tsarin Wafers na Wafers na LED

Daga ka'idar aiki ta LEDs, a bayyane yake cewa kayan wafer na epitaxial shine babban ɓangaren LED. A zahiri, manyan sigogi na optoelectronic kamar tsawon rai, haske, da ƙarfin lantarki na gaba galibi ana ƙaddara su ne ta hanyar kayan epitaxial. Fasaha da kayan aiki na Epitaxial wafer suna da mahimmanci ga tsarin ƙera, tare da Metal-Organic Chemical Vapor Deposition (MOCVD) shine babban hanyar haɓaka siraran yadudduka guda ɗaya na mahaɗan III-V, II-VI, da ƙarfe. Ga wasu sabbin abubuwa a nan gaba a fasahar wafer na epitaxial na LED.

1. Inganta Tsarin Ci Gaba Mai Mataki Biyu

A halin yanzu, samar da kayayyaki na kasuwanci yana amfani da tsarin girma matakai biyu, amma adadin substrates da za a iya lodawa a lokaci guda yana da iyaka. Duk da cewa tsarin wafer 6 ya girma, injinan da ke sarrafa kusan wafer 20 har yanzu suna kan ci gaba. Ƙara yawan wafers sau da yawa yakan haifar da rashin daidaito a cikin yadudduka na epitaxial. Ci gaban da za a samu nan gaba zai mayar da hankali kan hanyoyi biyu:

• Haɓaka fasahohin da ke ba da damar loda ƙarin substrates a cikin ɗakin amsawa guda ɗaya, wanda hakan ke sa su fi dacewa da manyan samarwa da rage farashi.
• Inganta kayan aiki masu sarrafa kansu sosai, masu maimaitawa sau ɗaya.

2. Fasaha ta Hydride Vapor Phase Epitaxy (HVPE)

Wannan fasaha tana ba da damar haɓaka fina-finai masu kauri da ƙarancin yawan nakasa, wanda zai iya zama substrates don haɓakar homoepitaxial ta amfani da wasu hanyoyi. Bugu da ƙari, fina-finan GaN da aka raba daga substrates na iya zama madadin manyan guntu-guntu guda ɗaya na GaN. Duk da haka, HVPE yana da rashin amfani, kamar wahalar sarrafa kauri daidai da iskar gas mai lalata waɗanda ke hana ci gaba da inganta tsarkin kayan GaN.

HVPE-GaN mai maganin Si-doped

(a) Tsarin na'urar HVPE-GaN mai Si-doped; (b) Hoton HVPE-GaN mai Si-doped mai kauri 800 μm;

(c) Rarraba yawan jigilar kaya kyauta tare da diamita na HVPE-GaN mai ɗauke da Si-doped

3. Fasahar Ci gaban Epitaxial ko Fasahar Ci gaban Epitaxial ta Zaɓaɓɓu

Wannan dabarar za ta iya ƙara rage yawan nakasa da kuma inganta ingancin lu'ulu'u na yadudduka na epitaxial na GaN. Tsarin ya ƙunshi:

• Ajiye wani Layer na GaN a kan wani abu mai dacewa (sapphire ko SiC).
• Ana saka wani abin rufe fuska na polycrystalline SiO₂ a saman.
• Amfani da photolithography da etching don ƙirƙirar tagogi na GaN da kuma layukan abin rufe fuska na SiO₂.A lokacin girma mai zuwa, GaN ya fara girma a tsaye a cikin tagogi sannan a gefe a kan layukan SiO₂.

Wafer ɗin GaN-on-Sapphire na XKH

4. Fasaha ta Pendeo-Epitaxy

Wannan hanyar tana rage lahani na lattice da rashin daidaiton zafi tsakanin substrate da epitaxial layer ke haifarwa sosai, wanda hakan ke ƙara inganta ingancin lu'ulu'u na GaN. Matakan sun haɗa da:

• Girman Layer na GaN a kan wani abu mai dacewa (6H-SiC ko Si) ta amfani da tsari mai matakai biyu.
• Yin zaɓaɓɓen zaɓaɓɓen layin epitaxial zuwa ƙasan substrate, ƙirƙirar ginshiƙi mai canzawa (GaN/buffer/substrate) da tsarin rami.
• Ƙara yawan layukan GaN, waɗanda suka miƙe daga gefen ginshiƙan GaN na asali, waɗanda aka rataye a kan ramukan.Tunda ba a amfani da abin rufe fuska ba, wannan yana hana hulɗa tsakanin GaN da kayan abin rufe fuska.

Wafer ɗin GaN-on-Silicon na XKH

5. Ƙirƙirar Kayan Aikin Hasken ...

Wannan yana shimfida harsashi mai ƙarfi ga fararen LEDs masu tushen phosphor masu sha'awar UV. Yawancin phosphors masu inganci za a iya jin daɗinsu ta hanyar hasken UV, suna ba da ingantaccen haske fiye da tsarin YAG:Ce na yanzu, don haka suna haɓaka aikin farin LED.

6. Fasahar Chip Rijiyar Quantum Mai Yawa (MQW)

A cikin tsarin MQW, ana zubar da ƙazanta daban-daban yayin girman layin fitar da haske don ƙirƙirar rijiyoyin quantum daban-daban. Haɗakar photons da ke fitowa daga waɗannan rijiyoyin yana samar da haske fari kai tsaye. Wannan hanyar tana inganta ingantaccen haske, rage farashi, kuma tana sauƙaƙa marufi da sarrafa da'ira, kodayake tana gabatar da ƙalubalen fasaha mafi girma.

7. Ci gaban Fasaha ta "Sake Amfani da Photon"

A watan Janairun 1999, Sumitomo na Japan ya ƙirƙiro farin LED ta amfani da kayan ZnSe. Fasahar ta ƙunshi haɓaka siraran fim na CdZnSe akan wani abu mai siffar lu'ulu'u ɗaya na ZnSe. Idan aka kunna wutar lantarki, fim ɗin yana fitar da haske mai launin shuɗi, wanda ke hulɗa da abin da ke cikin ZnSe don samar da haske mai launin rawaya, wanda ke haifar da haske fari. Hakazalika, Cibiyar Bincike ta Jami'ar Boston ta sanya wani abu mai suna AlInGaP semiconductor a kan wani abu mai launin shuɗi na GaN-LED don samar da haske fari.

8. Tsarin Wafer na Epitaxial na LED

① Ƙirƙirar Wafer Mai Juyawa:
Tsarin ƙasa → Tsarin gini → Girman Layer na Buffer → Girman Layer na GaN na nau'in N → Girman Layer na MQW mai fitar da haske → Girman Layer na GaN na nau'in P → Annealing → Gwaji (photoluminescence, X-ray) → Epitaxial wafer

② Ƙirƙirar Ƙwallon Gilashi:
Wafer mai siffar epitaxial → Tsarin abin rufe fuska da ƙera shi → Photolithography → Etching na ion → Electrode na nau'in N (deposition, annealing, etching) → Electrode na nau'in P (deposition, annealing, etching) → Dicing → Duba guntu da kuma kimanta shi.

Wafer ɗin GaN-on-SiC na ZMSH