1. Ma semiconductors a m'badwo wachitatu
Tekinoloje ya m'badwo woyamba wa semiconductor idapangidwa kutengera zida za semiconductor monga Si ndi Ge. Ndilo maziko azinthu zopangira ma transistors ndi ukadaulo wophatikizika wadera. Zida za semiconductor za m'badwo woyamba zidayika maziko amakampani opanga zamagetsi m'zaka za zana la 20 ndipo ndizo zida zoyambira ukadaulo wophatikizika wozungulira.
Zida za semiconductor za m'badwo wachiwiri makamaka zimaphatikizapo gallium arsenide, indium phosphide, gallium phosphide, indium arsenide, aluminium arsenide ndi mankhwala awo a ternary. Zida za semiconductor za m'badwo wachiwiri ndizo maziko amakampani azidziwitso a optoelectronic. Pazifukwa izi, mafakitale okhudzana nawo monga kuyatsa, mawonedwe, laser, ndi photovoltaics apangidwa. Amagwiritsidwa ntchito kwambiri muukadaulo wazidziwitso zamakono komanso mafakitale owonetsera optoelectronic.
Zida zoyimilira zida za m'badwo wachitatu za semiconductor zimaphatikizapo gallium nitride ndi silicon carbide. Chifukwa cha kusiyana kwawo kwakukulu kwa bandi, kuthamanga kwambiri kwa ma elekitironi akuchulukirachulukira, kukhathamiritsa kwamafuta kwambiri, komanso kulimba kwamunda, ndi zida zabwino zokonzekera kachulukidwe kamphamvu kwambiri, ma frequency apamwamba, ndi zida zamagetsi zotayika pang'ono. Pakati pawo, zida zamagetsi za silicon carbide zili ndi mwayi wogwiritsa ntchito mphamvu zambiri, kugwiritsa ntchito mphamvu zochepa, komanso kukula kochepa, komanso kukhala ndi chiyembekezo chogwiritsa ntchito magalimoto atsopano, ma photovoltaics, mayendedwe anjanji, deta yayikulu, ndi magawo ena. Zida za Gallium nitride RF zili ndi ubwino wafupipafupi, mphamvu zambiri, bandwidth yaikulu, kugwiritsira ntchito mphamvu zochepa ndi kukula kochepa, ndipo zimakhala ndi chiyembekezo chogwiritsa ntchito mauthenga a 5G, Internet of Things, radar yankhondo ndi zina. Kuphatikiza apo, zida zamagetsi zochokera ku gallium nitride zakhala zikugwiritsidwa ntchito kwambiri pagawo lamagetsi otsika. Kuphatikiza apo, m'zaka zaposachedwa, zida zomwe zikubwera za gallium oxide zikuyembekezeka kupanga ukadaulo wogwirizana ndiukadaulo womwe ulipo wa SiC ndi GaN, ndikukhala ndi chiyembekezo chogwiritsa ntchito m'magawo otsika komanso okwera kwambiri.
Poyerekeza ndi zida za semiconductor za m'badwo wachitatu, zida za semiconductor za m'badwo wachitatu zili ndi bandgap yotakata (m'lifupi mwake bandgap ya Si, zomwe zimayambira m'badwo woyamba wa semiconductor, ndi pafupifupi 1.1eV, m'lifupi bandgap wa GaAs, wamba. zinthu za m'badwo wachiwiri semiconductor zakuthupi, pafupifupi 1.42eV, ndi bandgap m'lifupi mwake. GaN, chinthu chodziwika bwino cha m'badwo wachitatu wa semiconductor, ndi pamwamba pa 2.3eV), kukana kwamphamvu kwa radiation, kukana kwambiri kugwa kwamagetsi, komanso kukana kutentha kwambiri. Zida za m'badwo wachitatu za semiconductor zokhala ndi bandgap m'lifupi ndizoyenera kupanga zida zamagetsi zosagwira ma radiation, ma frequency apamwamba, amphamvu kwambiri komanso ophatikizika kwambiri. Kugwiritsa ntchito kwawo pazida zamawayilesi a microwave, ma LED, ma lasers, zida zamagetsi ndi magawo ena akopa chidwi kwambiri, ndipo awonetsa chiyembekezo chokulirapo pamalumikizidwe am'manja, ma gridi anzeru, mayendedwe anjanji, magalimoto amagetsi atsopano, zamagetsi zamagetsi, ndi ultraviolet ndi buluu. -zida zowala zobiriwira [1].
Gwero lachithunzi: CASA, Zheshang Securities Research Institute
Chithunzi 1 GaN mphamvu ya chipangizo chanthawi yake ndi zoneneratu
II GaN zakuthupi kapangidwe ndi makhalidwe
GaN ndi semiconductor yolunjika ya bandgap. The bandgap m'lifupi mwa dongosolo wurtzite kutentha firiji ndi za 3.26eV. Zida za GaN zili ndi zida zitatu zazikulu za kristalo, zomwe ndi mawonekedwe a wurtzite, kapangidwe ka sphalerite ndi kapangidwe ka mchere wamchere. Pakati pawo, mawonekedwe a wurtzite ndiwokhazikika kwambiri a kristalo. Chithunzi 2 ndi chithunzi cha mawonekedwe a hexagonal wurtzite a GaN. Kapangidwe ka wurtzite ka zinthu za GaN ndi kapangidwe ka hexagonal kotsekeka. Selo lililonse lili ndi ma atomu 12, kuphatikiza ma atomu 6 N ndi ma atomu 6 a Ga. Atomu iliyonse ya Ga (N) imapanga mgwirizano ndi ma atomu 4 apafupi a N (Ga) ndipo amasanjidwa motsatira ABABAB…
Chithunzi cha 2 Wurtzite kapangidwe ka GaN crystal cell diagram
III Magawo omwe amagwiritsidwa ntchito kawirikawiri a GaN epitaxy
Zikuwoneka kuti epitaxy yofanana pa magawo a GaN ndiye chisankho chabwino kwambiri pa epitaxy ya GaN. Komabe, chifukwa cha mphamvu yayikulu yomangira ya GaN, kutentha kukafika posungunuka 2500 ℃, kuthamanga kwake kofananirako kuli pafupifupi 4.5GPa. Pamene kuthamanga kwa kuwonongeka kuli kochepa kuposa kupanikizika kumeneku, GaN sisungunuka koma imawola mwachindunji. Izi zimapangitsa matekinoloje okhwima okonzekera gawo lapansi monga njira ya Czochralski kukhala yosayenera pokonzekera magawo a kristalo a GaN, zomwe zimapangitsa kuti magawo a GaN akhale ovuta kupanga komanso okwera mtengo. Choncho, magawo omwe amagwiritsidwa ntchito kwambiri pakukula kwa GaN epitaxial makamaka Si, SiC, safiro, etc. [3].
Tchati 3 GaN ndi magawo a zinthu zomwe zimagwiritsidwa ntchito kwambiri
GaN epitaxy pa safire
Sapphire ili ndi mankhwala okhazikika, ndi otsika mtengo, ndipo ali ndi kukhwima kwakukulu kwa makampani akuluakulu opanga zinthu. Chifukwa chake, yakhala imodzi mwazinthu zakale kwambiri komanso zogwiritsidwa ntchito kwambiri pazida za semiconductor. Monga amodzi mwa magawo omwe amagwiritsidwa ntchito kwambiri pa GaN epitaxy, zovuta zazikulu zomwe ziyenera kuthetsedwa pagawo la safiro ndi:
✔ Chifukwa cha kusiyana kwakukulu kwa latisi pakati pa safiro (Al2O3) ndi GaN (pafupifupi 15%), kachulukidwe kachilema pamawonekedwe apakati pa epitaxial layer ndi gawo lapansi ndipamwamba kwambiri. Pofuna kuchepetsa zotsatira zake zoipa, gawo lapansili liyenera kuchitidwa movutikira njira ya epitaxy isanayambe. Musanakulire epitaxy ya GaN pamadzi a safiro, gawo lapansi liyenera kutsukidwa bwino kuti lichotse zowononga, zowonongeka zotsalira, ndi zina zotero, ndikupanga masitepe ndi masitepe apamwamba. Ndiye, gawo lapansi pamwamba ndi nitrided kusintha kunyowetsa katundu wa epitaxial wosanjikiza. Pomaliza, malo ocheperako a AlN (nthawi zambiri 10-100nm wokhuthala) amayenera kuikidwa pagawo laling'ono ndikumangirizidwa pa kutentha kochepa kuti akonzekere kukula komaliza kwa epitaxial. Ngakhale zili choncho, kachulukidwe kakachuluke m'mafilimu a GaN epitaxial omwe amamera pazigawo za safiro akadali apamwamba kuposa amafilimu a homoepitaxial (pafupifupi 1010cm-2, poyerekeza ndi kusasunthika kwa zero m'mafilimu a silicon homoepitaxial kapena gallium arsenide homoepitaxial films 10cm2, kapena pakati pa 10cm2. 2). Kuchuluka kwa chilema kumachepetsa kuyenda kwa chonyamulira, potero kufupikitsa moyo wonyamula anthu ochepa ndikuchepetsa kutenthetsa kwamafuta, zomwe zidzachepetsa magwiridwe antchito a chipangizocho [4];
✔ Mafuta owonjezera a safiro ndi ochulukirapo kuposa a GaN, kotero kuti biaxial compressive stress imapangidwa mu epitaxial layer panthawi ya kuzizira kuchokera ku kutentha kwa kutentha kupita ku kutentha kwa chipinda. Kwa mafilimu owonjezera a epitaxial, kupanikizika kumeneku kungayambitse kusweka kwa filimuyo kapena ngakhale gawo lapansi;
✔ Poyerekeza ndi magawo ena, matenthedwe amtundu wa safiro ndi otsika (pafupifupi 0.25W * cm-1 * K-1 pa 100 ℃), ndipo ntchito yotulutsa kutentha imakhala yosauka;
✔ Chifukwa cha kusayenda bwino, magawo a safiro samathandizira kuphatikiza ndikugwiritsa ntchito ndi zida zina za semiconductor.
Ngakhale kuchuluka kwa chilema kwa zigawo za GaN epitaxial zomwe zimakula pazigawo za safiro ndizokwera kwambiri, sizikuwoneka kuti zimachepetsa kwambiri magwiridwe antchito a optoelectronic a ma LED obiriwira amtundu wa GaN, kotero kuti magawo a safiro amagwiritsidwabe ntchito kwambiri ma LED opangidwa ndi GaN.
Ndi kupanga kwatsopano kwa zida za GaN monga ma lasers kapena zida zina zamphamvu zolimba kwambiri, zolakwika zomwe zidapangidwa ndi miyala ya safiro zakhala zolepheretsa kugwiritsa ntchito kwawo. Kuonjezera apo, ndi chitukuko cha teknoloji ya kukula kwa gawo la SiC, kuchepetsa mtengo komanso kukhwima kwa teknoloji ya GaN epitaxial pa magawo a Si, kufufuza kwina pakukula kwa zigawo za GaN epitaxial pazigawo za safiro kwawonetsa pang'onopang'ono kuzizira.
GaN epitaxy pa SiC
Poyerekeza ndi safiro, magawo a SiC (4H- ndi 6H-crystals) ali ndi kusiyana kochepa kwa lattice ndi zigawo za GaN epitaxial (3.1%, zofanana ndi [0001] mafilimu a epitaxial), kutenthetsa kwapamwamba (pafupifupi 3.8W * cm-1 * K) -1), etc. Kuphatikiza apo, ma conductivity a magawo a SiC amalolanso kuti kulumikizana kwamagetsi kupangidwe kumbuyo kwa gawo lapansi, zomwe zimathandiza kuti chipangizochi chikhale chosavuta. Kukhalapo kwa zabwinozi kwakopa ofufuza ochulukirapo kuti agwire ntchito ya GaN epitaxy pa silicon carbide substrates.
Komabe, kugwira ntchito mwachindunji pamagawo a SiC kuti mupewe kukula kwa ma epilayers a GaN kumakumananso ndi zovuta zingapo, kuphatikiza izi:
✔ Kukhwimira kwapamadzi kwa magawo a SiC ndikokwera kwambiri kuposa kwa safiro (kuuma kwa safiro 0.1nm RMS, SiC roughness 1nm RMS), magawo a SiC amakhala ndi kuuma kwakukulu komanso kusagwira bwino ntchito, ndipo kuuma uku ndi kuwonongeka kotsalira kopukutira ndi chimodzi mwazo. magwero a zolakwika mu GaN epilayers.
✔ The screw dislocation density of SiC substrates is high (dislocation density 103-104cm-2), screw dislocations akhoza kufalikira ku GaN epilayer ndi kuchepetsa ntchito chipangizo;
✔ Kapangidwe ka atomiki pamtunda wapansi panthaka kumapangitsa kuti pakhale zolakwika za stacking (BSFs) mu epilayer ya GaN. Kwa epitaxial GaN pa magawo a SiC, pali madongosolo angapo a ma atomiki otheka pagawo laling'ono, zomwe zimapangitsa kuti pakhale kusagwirizana koyambirira kwa ma atomiki amtundu wa epitaxial GaN wosanjikiza pamenepo, womwe umakonda kusungika zolakwika. Kuwonongeka kwa stacking (SFs) kumayambitsa minda yamagetsi yomangidwa motsatira c-axis, zomwe zimayambitsa mavuto monga kutayikira kwa zida zolekanitsa zonyamula ndege;
✔ Kukula kwa kutentha kwa gawo la gawo la SiC ndilaling'ono kuposa la AlN ndi GaN, zomwe zimayambitsa kupsinjika kwa kutentha pakati pa epitaxial layer ndi gawo lapansi panthawi yozizira. Waltereit ndi Brand adaneneratu kutengera zotsatira za kafukufuku wawo kuti vutoli litha kuchepetsedwa kapena kuthetsedwa mwakukula zigawo za epitaxial za GaN pazigawo zopyapyala, zosakanikirana bwino za AlN nucleation;
✔ Vuto la kusanyowa bwino kwa ma atomu a Ga. Mukakulitsa zigawo za GaN epitaxial molunjika pamtunda wa SiC, chifukwa cha kunyowa kosauka pakati pa maatomu awiriwo, GaN imakonda kukula kwa chilumba cha 3D pamtunda wapansi. Kuwonetsa buffer layer ndiyo njira yomwe imagwiritsidwa ntchito kwambiri popititsa patsogolo luso la epitaxial mu GaN epitaxy. Kuyambitsa AlN kapena AlxGa1-xN bafa wosanjikiza kungathandize bwino kunyowa kwa SiC pamwamba ndikupangitsa kuti GaN epitaxial layer ikule mu miyeso iwiri. Kuphatikiza apo, imathanso kuwongolera kupsinjika ndikuletsa zolakwika za gawo lapansi kuti zipitirire ku GaN epitaxy;
✔ Ukadaulo wokonzekera magawo a SiC ndiwasakhwima, mtengo wagawo ndi wokwera, ndipo pali ogulitsa ochepa komanso operekera pang'ono.
Kafukufuku wa Torres et al. akuwonetsa kuti kuyika gawo laling'ono la SiC ndi H2 kutentha kwambiri (1600 ° C) isanakwane epitaxy imatha kupanga masitepe okhazikika pamtunda, potero amapeza filimu yapamwamba kwambiri ya AlN epitaxial kuposa momwe ilili mwachindunji. wakula pamtunda woyambira gawo lapansi. Kafukufuku wa Xie ndi gulu lake akuwonetsanso kuti kuyika makonzedwe a silicon carbide substrate kumatha kupititsa patsogolo mawonekedwe a pamwamba ndi mtundu wa crystal wa GaN epitaxial layer. Smith ndi al. adapeza kuti kusuntha kwa ulusi kuchokera kugawo laling'ono laling'ono / malo otchinga ndi malo otchinga / epitaxial layers amagwirizana ndi kusalala kwa gawo lapansi [5].
Chithunzi cha 4 TEM morphology ya zitsanzo za GaN epitaxial layer zomwe zakula pa 6H-SiC substrate (0001) pansi pazikhalidwe zosiyanasiyana za mankhwala (a) kuyeretsa mankhwala; (b) kuyeretsa mankhwala + mankhwala a hydrogen plasma; (c) kuyeretsa mankhwala + hydrogen plasma mankhwala + 1300 ℃ hydrogen kutentha mankhwala kwa 30min
GaN epitaxy pa Si
Poyerekeza ndi silicon carbide, safiro ndi magawo ena, njira yokonzekera gawo lapansi ya silicon ndi yokhwima, ndipo imatha kupereka magawo okhwima okhwima omwe ali ndi mtengo wokwera kwambiri. Panthawi imodzimodziyo, kutentha kwa kutentha ndi kutulutsa magetsi ndi zabwino, ndipo njira ya Si electronic device ndi yokhwima. Kuthekera kophatikiza mwangwiro zida za optoelectronic GaN ndi zida zamagetsi za Si mtsogolo kumapangitsanso kukula kwa GaN epitaxy pa silicon kukhala kokongola kwambiri.
Komabe, chifukwa cha kusiyana kwakukulu kwa ma lattice osinthasintha pakati pa Si gawo lapansi ndi zinthu za GaN, epitaxy yosiyana kwambiri ya GaN pa Si gawo lapansi ndi vuto lalikulu losagwirizana, ndipo likufunikanso kukumana ndi zovuta zingapo:
✔ Vuto lamphamvu la mawonekedwe apamwamba. Pamene GaN ikukula pa gawo la Si, pamwamba pa gawo la Si lidzayamba kupangidwa nitrided kupanga amorphous silicon nitride wosanjikiza zomwe sizikugwirizana ndi nucleation ndi kukula kwa high-density GaN. Kuonjezera apo, Si pamwamba idzalumikizana ndi Ga, yomwe idzawononga pamwamba pa gawo la Si. Pa kutentha kwambiri, kuwonongeka kwa Si pamwamba kudzafalikira mu GaN epitaxial layer kuti apange mawanga akuda a silicon.
✔ Kusagwirizana kosalekeza kwa lattice pakati pa GaN ndi Si ndi kwakukulu (~ 17%), zomwe zidzapangitsa kuti pakhale kusungunuka kwa ulusi wambiri komanso kuchepetsa kwambiri khalidwe la epitaxial layer;
✔ Poyerekeza ndi Si, GaN ili ndi chowonjezera chokulirapo chamafuta (GaN's coefficient of thermal expansion coefficient ya 5.6 × 10-6K-1, Si's thermal coefficient is about 2.6 × 10-6K-1), ndipo ming'alu ikhoza kupangidwa mu GaN epitaxial wosanjikiza pa kuzizira kwa kutentha kwa epitaxial kutentha kwa chipinda;
✔ Si imakhudzidwa ndi NH3 pa kutentha kwambiri kuti ipange polycrystalline SiNx. AlN sangathe kupanga nyukiliya yokonda kwambiri pa polycrystalline SiNx, yomwe imayambitsa kusokonezeka kwa GaN wosanjikiza wokulirapo komanso kuchuluka kwa zolakwika, zomwe zimapangitsa kuti pakhale kristalo wocheperako wa GaN epitaxial layer, komanso ngakhale kuvutika kupanga single-crystalline. GaN epitaxial layer [6].
Pofuna kuthetsa vuto la kusagwirizana kwakukulu kwa lattice, ofufuza ayesa kuyambitsa zipangizo monga AlAs, GaAs, AlN, GaN, ZnO, ndi SiC monga zigawo za buffer pa Si substrates. Pofuna kupewa mapangidwe a polycrystalline SiNx ndi kuchepetsa zotsatira zake zoipa pa khalidwe la kristalo la zipangizo za GaN / AlN / Si (111), TMAl nthawi zambiri imayenera kuyambitsidwa kwa nthawi inayake isanayambe kukula kwa epitaxial kwa AlN buffer layer. kuteteza NH3 kuti isachite ndi mawonekedwe owonekera a Si kuti apange SiNx. Kuonjezera apo, matekinoloje a epitaxial monga teknoloji yapakatikati yapansi angagwiritsidwe ntchito kupititsa patsogolo khalidwe la epitaxial layer. Kukula kwa matekinolojewa kumathandiza kulepheretsa mapangidwe a SiNx pa mawonekedwe a epitaxial, kulimbikitsa kukula kwa magawo awiri a GaN epitaxial layer, ndi kupititsa patsogolo kukula kwa epitaxial layer. Kuphatikiza apo, gulu la AlN buffer limayambitsidwa kuti lithandizire kupsinjika kwamphamvu komwe kumachitika chifukwa cha kusiyana kwa ma coefficients okulitsa kutentha kuti apewe ming'alu ya GaN epitaxial layer pa silicon substrate. Kafukufuku wa Krost akuwonetsa kuti pali kulumikizana kwabwino pakati pa makulidwe a AlN buffer wosanjikiza ndikuchepetsa kupsinjika. Pamene makulidwe a bafa afika 12nm, epitaxial wosanjikiza wokhuthala kuposa 6μm imatha kukulitsidwa pagawo la silicon kudzera mu dongosolo loyenera lakukula popanda kusweka kwa epitaxial.
Pambuyo poyesa kwa nthawi yaitali ndi ochita kafukufuku, ubwino wa zigawo za GaN epitaxial zomwe zakula pazitsulo za silicon zakhala zikuyenda bwino kwambiri, ndipo zipangizo monga transistors zamunda, Schottky barrier ultraviolet detectors, ma LED obiriwira a buluu ndi ma ultraviolet lasers apita patsogolo kwambiri.
Mwachidule, popeza magawo omwe amagwiritsidwa ntchito kawirikawiri a GaN epitaxial onse ndi epitaxy yosiyana, onse amakumana ndi mavuto ofanana monga kusagwirizana kwa lattice ndi kusiyana kwakukulu kwa ma coefficients owonjezera kutentha ku madigiri osiyanasiyana. Magawo a Homogeneous epitaxial GaN amachepetsedwa ndi kukhwima kwaukadaulo, ndipo magawowo sanapangidwebe mochuluka. Mtengo wopangira ndi wokwera, kukula kwa gawo lapansi ndi kakang'ono, ndipo mtundu wa gawo lapansi siwoyenera. Kupanga magawo atsopano a GaN epitaxial ndi kuwongolera khalidwe la epitaxial akadali chimodzi mwa zinthu zofunika zomwe zimalepheretsa chitukuko cha GaN epitaxial industry.
IV. Njira zodziwika bwino za GaN epitaxy
MOCVD (chemical vapor deposition)
Zikuwoneka kuti epitaxy yofanana pa magawo a GaN ndiye chisankho chabwino kwambiri pa epitaxy ya GaN. Komabe, popeza ma precursors a mankhwala nthunzi deposition ndi trimethylgallium ndi ammonia, ndi mpweya chonyamulira ndi hydrogen, mmene MOCVD kukula kutentha ndi za 1000-1100 ℃, ndi kukula kwa MOCVD ndi pafupifupi ma microns ochepa pa ola. Itha kupanga mawonekedwe otsetsereka pamlingo wa atomiki, womwe ndi woyenera kwambiri kukula kwa ma heterojunctions, zitsime za quantum, superlattices ndi zina. Kukula kwake kofulumira, kufanana kwabwino, komanso kukwanira kwa kukula kwa madera akuluakulu ndi magawo ambiri nthawi zambiri amagwiritsidwa ntchito popanga mafakitale.
MBE (molecular beam epitaxy)
Mu molecular beam epitaxy, Ga amagwiritsa ntchito gwero loyambira, ndipo nayitrogeni yogwira imapezeka kuchokera ku nayitrogeni kudzera mu RF plasma. Poyerekeza ndi njira MOCVD, ndi MBE kukula kutentha ndi za 350-400 ℃ m'munsi. Kutsika kwa kutentha kwa kukula kumatha kupewa kuipitsidwa kwina komwe kungayambike chifukwa cha kutentha kwambiri. Dongosolo la MBE limagwira ntchito pansi pa ultra-high vacuum, yomwe imalola kuti iphatikize njira zodziwira zambiri mu-situ. Panthawi imodzimodziyo, kukula kwake ndi mphamvu zopanga sizingafanane ndi MOCVD, ndipo zimagwiritsidwa ntchito kwambiri mu kafukufuku wa sayansi [7].
Chithunzi 5 (a) Eiko-MBE schematic (b) MBE main reaction chamber schematic
Njira ya HVPE (hydride vapor phase epitaxy)
Ma precursors a hydride vapor phase epitaxy njira ndi GaCl3 ndi NH3. Detchprohm et al. adagwiritsa ntchito njira iyi kukulitsa GaN epitaxial wosanjikiza mazana a ma microns wokhuthala pamwamba pa gawo lapansi la safiro. Pakuyesa kwawo, gawo la ZnO linakula pakati pa gawo lapansi la safiro ndi epitaxial layer ngati chotchinga chotchinga, ndipo gawo la epitaxial linachotsedwa pagawo. Poyerekeza ndi MOCVD ndi MBE, mbali yaikulu ya njira ya HVPE ndi kukula kwake kwakukulu, komwe kuli koyenera kupanga zigawo zazikulu ndi zipangizo zambiri. Komabe, pamene makulidwe a epitaxial wosanjikiza amaposa 20μm, epitaxial wosanjikiza opangidwa ndi njira imeneyi sachedwa ming'alu.
Akira USUI adayambitsa ukadaulo wapagawo wagawo kutengera njira iyi. Poyamba anakula 1-1.5μm wokhuthala kwambiri wa GaN epitaxial pagawo la safiro pogwiritsa ntchito njira ya MOCVD. Epitaxial layer inali ndi 20nm wandiweyani wa GaN buffer wosanjikiza womwe umakula pansi pa kutentha kochepa komanso GaN wosanjikiza wokulira pansi pa kutentha kwambiri. Kenaka, pa 430 ℃, gawo la SiO2 linayikidwa pamwamba pa epitaxial layer, ndipo mikwingwirima yawindo inapangidwa pa filimu ya SiO2 ndi photolithography. Kutalikirana kwa mizere kunali 7μm ndipo m'lifupi mwake chigoba chinali kuyambira 1μm mpaka 4μm. Pambuyo pakusintha kumeneku, adapeza gawo la GaN epitaxial pagawo la safiro la 2-inchi lomwe linali lopanda ming'alu komanso losalala ngati galasi ngakhale makulidwe ake adakula mpaka makumi kapena mazana a ma microns. Kachulukidwe kachilemako adachepetsedwa kuchokera ku 109-1010cm-2 ya njira yachikhalidwe ya HVPE mpaka pafupifupi 6 × 107cm-2. Iwo ananenanso mu kuyesera kuti pamene mlingo kukula kuposa 75μm/h, chitsanzo pamwamba adzakhala akhakula[8].
Chithunzi 6 Graphical Substrate Schematic
V. Chidule ndi Outlook
Zida za GaN zidayamba kuonekera mu 2014 pomwe kuwala kwa buluu kunapambana Mphotho ya Nobel mu Fizikisi chaka chimenecho, ndikulowa m'malo a anthu olipira mwachangu pantchito zamagetsi zamagetsi. M'malo mwake, mapulogalamu amagetsi okulitsa mphamvu ndi zida za RF zomwe zimagwiritsidwa ntchito pamasiteshoni a 5G omwe anthu ambiri sangawone adatulukiranso mwakachetechete. M'zaka zaposachedwa, kutsogola kwa zida zamagetsi zamagalimoto opangidwa ndi GaN kukuyembekezeka kutsegulira msika watsopano wa GaN.
Kufunika kwakukulu kwa msika kudzalimbikitsadi chitukuko cha mafakitale ndi matekinoloje okhudzana ndi GaN. Ndi kukhwima ndi kusintha kwa makina okhudzana ndi mafakitale okhudzana ndi GaN, mavuto omwe akukumana nawo ndi luso lamakono la GaN epitaxial pamapeto pake adzawongoleredwa kapena kugonjetsedwa. M'tsogolomu, anthu apanga ukadaulo watsopano wa epitaxial ndi njira zabwino kwambiri zapansi panthaka. Pofika nthawiyo, anthu azitha kusankha ukadaulo wofufuzira wakunja woyenera kwambiri ndikuyika magawo osiyanasiyana ogwiritsira ntchito molingana ndi momwe amagwiritsidwira ntchito, ndikupanga zinthu zopikisana kwambiri.
Nthawi yotumiza: Jun-28-2024