I-Silicon Carbide Epitaxy: Imigaqo yeNkqubo, Ulawulo lokuThinteka, kunye nemingeni yeziphene

I-silicon carbide (SiC) epitaxy isembindini wenguqu yamandla e-elektroniki yanamhlanje. Ukusuka kwizithuthi zombane ukuya kwiinkqubo zamandla avuselelekayo kunye nee-industrial drives ezine-voltage ephezulu, ukusebenza kunye nokuthembeka kwezixhobo ze-SiC kuxhomekeke kancinci kuyilo lwesekethe kunokuba kuxhomekeke kwinto eyenzekayo ngexesha le-micrometer ezimbalwa zokukhula kwekristale kumphezulu we-wafer. Ngokungafaniyo ne-silicon, apho i-epitaxy yinkqubo evuthiweyo nexolelayo, i-SiC epitaxy ngumsebenzi ochanekileyo nongaxoleliyo kulawulo lwesikali se-athomu.

Eli nqaku liphonononga indlelaI-SiC epitaxyiyasebenza, kutheni ulawulo lobukhulu lubaluleke kangaka, kwaye kutheni iziphene zihlala zingomnye wemingeni enzima kuyo yonke ikhonkco lokubonelela ngeSiC.

1. Yintoni iSiC Epitaxy kwaye kutheni ibalulekile?

I-Epitaxy ibhekisa ekukhuleni komaleko wekristale olungelelwaniso lweathomu olulandela olo lwe-substrate engaphantsi. Kwizixhobo zamandla ze-SiC, lo maleko we-epitaxial wenza ummandla osebenzayo apho kuchazwa khona ukuvimba i-voltage, ukuqhuba kwamandla, kunye nokuziphatha kokutshintsha.

Ngokungafaniyo nezixhobo ze-silicon, ezihlala zixhomekeke kwi-bulk doping, izixhobo ze-SiC zixhomekeke kakhulu kwiileya ze-epitaxial ezinobukhulu obucwangcisiweyo ngononophelo kunye neeprofayili ze-doping. Umahluko we-micrometer enye kubukhulu be-epitaxial unokutshintsha kakhulu i-voltage yokuqhekeka, ukumelana noxinzelelo, kunye nokuthembeka kwexesha elide.

Ngamafutshane, i-SiC epitaxy ayisiyonkqubo exhasayo—ichaza isixhobo.

2. Iziseko zoKhulo lweSiC Epitaxial

Uninzi lwe-epitaxy ye-SiC yorhwebo lwenziwa kusetyenziswa i-chemical vapor deposition (CVD) kumaqondo obushushu aphezulu kakhulu, aqhele ukuba phakathi kwe-1,500 °C kunye ne-1,650 °C. Iigesi ze-Silane kunye ne-hydrocarbon zifakwa kwi-reactor, apho ii-athomu ze-silicon kunye ne-carbon zibola kwaye ziphinde zihlangane kumphezulu we-wafer.

Zininzi izinto ezenza i-SiC epitaxy ibe nzima ngakumbi kune-silicon epitaxy:

• Ubudlelwane obuqinileyo be-covalent phakathi kwe-silicon kunye ne-carbon

• Amaqondo obushushu aphezulu okukhula asondele kwimida yozinzo lwezinto

• Uvakalelo kumanyathelo omphezulu kunye nokusikwa kakubi kwe-substrate

• Ubukho bee-polytypes ezininzi ze-SiC

Nokuba ukuphambuka okuncinci kwindlela igesi ehamba ngayo, ukufana kobushushu, okanye ukulungiswa komphezulu kunokuvelisa iziphene ezisasazeka kumaleko we-epitaxial.

3. Ulawulo Lobukhulu: Kutheni iiMicrometers Zibalulekile

Kwizixhobo zamandla zeSiC, ubukhulu be-epitaxial bumisela ngokuthe ngqo amandla ombane. Umzekelo, isixhobo se-1,200 V sinokufuna umaleko we-epitaxial onama-micrometer ambalwa kuphela ubukhulu, ngelixa isixhobo se-10 kV sinokufuna amashumi ee-micrometer.

Ukufikelela kubukhulu obufanayo kwi-wafer yonke eyi-150 mm okanye eyi-200 mm ngumceli mngeni omkhulu wobunjineli. Utshintsho oluncinci njenge-±3% lunokukhokelela koku:

• Ukusasazwa kwentsimi yombane okungalinganiyo

• Ukuncipha kwemingcele yevolthi yokuqhekeka

• Ukungasebenzi kakuhle kwesixhobo ukusuka kwesinye isixhobo ukuya kwesinye

Ulawulo lokutyeba luba nzima ngakumbi ngenxa yesidingo soxinzelelo oluchanekileyo lwe-doping. Kwi-SiC epitaxy, ukutyeba kunye ne-doping zidityaniswe ngokuqinileyo—ukulungisa enye kudla ngokuchaphazela enye. Oku kuxhomekeke kwenye kunyanzela abavelisi ukuba balinganisele izinga lokukhula, ukufana, kunye nomgangatho wezinto ngaxeshanye.

4. Iziphene: Umngeni Oqhubekayo

Nangona kukho inkqubela phambili ekhawulezileyo kushishino, iziphene zisengumqobo ophambili kwi-SiC epitaxy. Ezinye zezona ntlobo zeziphene zibalulekileyo ziquka:

• Ukudilika kwe-Basal plane, enokwanda ngexesha lokusebenza kwesixhobo kwaye ibangele ukonakala kwe-bipolar

• Iziphene zokubeka izinto ngokwee-stacking, edla ngokubangelwa kukukhula kwe-epitaxial

• Iimbhobho ezincinci, incitshiswe kakhulu kwiindawo zanamhlanje kodwa isenempembelelo kwisivuno

• Iziphene zekaroti kunye neziphene ezinxantathu, enxulumene nokungazinzi kokukhula kwendawo

Okwenza iziphene ze-epitaxial zibe yingxaki ngakumbi kukuba ezininzi zivela kwi-substrate kodwa ziyaguquka ngexesha lokukhula. I-wafer ebonakala ivumelekile inokuba neziphene ezisebenzayo ngombane kuphela emva kwe-epitaxy, nto leyo eyenza kube nzima ukuxilonga kwangethuba.

5. Indima yoMgangatho weSubstrate

I-Epitaxy ayinakuyilungisa i-substrates engalunganga. Uburhabaxa bomphezulu, i-angle engalunganga, kunye noxinano lwe-basal plane dislocation zonke zinefuthe elikhulu kwiziphumo ze-epitaxial.

Njengoko ububanzi be-wafer bukhula ukusuka kwi-150 mm ukuya kwi-200 mm nangaphezulu, ukugcina umgangatho we-substrate ofanayo kuba nzima. Kwanotshintsho oluncinci kwi-wafer lunokuguqula umahluko omkhulu kwindlela yokuziphatha kwe-epitaxial, ukwandisa ubunzima benkqubo kunye nokunciphisa isivuno iyonke.

Olu qhagamshelo oluqinileyo phakathi kwe-substrate kunye ne-epitaxy sesinye sezizathu zokuba uthotho lwe-SiC ludityaniswe ngokuthe nkqo ngakumbi kune-silicon counterpart yayo.

6. Imingeni yokwandisa ubungakanani beWafer enkulu

Ukutshintshela kwii-wafers ezinkulu ze-SiC kwandisa yonke imingeni ye-epitaxial. Ii-gradients zobushushu ziba nzima ukuzilawula, ukufana kokuhamba kwegesi kuba lula ngakumbi, kwaye iindlela zokusasaza iziphene ziyanda.

Kwangaxeshanye, abavelisi bezixhobo zamandla bafuna iinkcukacha eziqinileyo: ukulinganiswa kwamandla aphezulu, uxinano oluphantsi lweziphene, kunye nokuhambelana okungcono kwe-wafer ukuya kwi-wafer. Iinkqubo ze-Epitaxy ke ngoko kufuneka zifikelele kulawulo olungcono ngelixa zisebenza kwizikali ezingazange zicingelwe ekuqaleni kwi-SiC.

Olu xinzelelo luchaza uninzi lwezinto ezintsha zanamhlanje kuyilo lwe-epitaxial reactor kunye nokwenza ngcono inkqubo.

7. Kutheni i-SiC Epitaxy ichaza uQoqosho lweZixhobo

Kwimveliso ye-silicon, i-epitaxy idla ngokuba yinto ebiza kakhulu. Kwimveliso ye-SiC, inika ixabiso.

I-Epitaxial yield imisela ngokuthe ngqo ukuba zingaphi ii-wafers ezinokungena kwimveliso yesixhobo, kwaye zingaphi izixhobo ezigqityiweyo ezihlangabezana neemfuno. Ukuncipha okuncinci koxinano lwesiphene okanye umahluko wobukhulu kunokuguqulela ekunciphiseni okukhulu kweendleko kwinqanaba lenkqubo.

Yingakho inkqubela phambili kwi-SiC epitaxy idla ngokuba nefuthe elikhulu ekusetyenzisweni kwemarike kunempumelelo eyenzekileyo kuyilo lwezixhobo ngokwazo.

8. Ukujonga Phambili

I-SiC epitaxy iyaqhubeka isuka kubugcisa iye kwisayensi, kodwa ayikafikeleli ekuvuthweni kwe-silicon. Inkqubela phambili eqhubekayo iya kuxhomekeka ekubekweni esweni ngcono kwindawo ethile, ulawulo oluqinileyo lwe-substrate, kunye nokuqonda okunzulu iindlela zokwakheka kweziphene.

Njengoko amandla e-elektroniki esiya kwii-voltage eziphezulu, amaqondo obushushu aphezulu, kunye nemigangatho ephezulu yokuthembeka, i-epitaxy iya kuhlala iyinkqubo ezolileyo kodwa egqibeleleyo ebumba ikamva lobuchwepheshe be-SiC.

Ekugqibeleni, ukusebenza kweenkqubo zamandla zesizukulwana esilandelayo kunokumiselwa kungengazo iidayagram zesekethe okanye izinto ezintsha zokupakisha, kodwa ngendlela ezibekwe ngayo ngokuchanekileyo iiathom—umaleko omnye we-epitaxial ngexesha.