Ubuchwepheshe obuyisisekelo bokukhula kweI-SiC epitaxializinto ezisetshenziswayo okokuqala ziwubuchwepheshe bokulawula amaphutha, ikakhulukazi ubuchwepheshe bokulawula ukungalungi obuthambekele ekuhlulekeni kwedivayisi noma ukucekelwa phansi kokwethembeka. Ukucwaninga kwendlela yokukhubazeka kwe-substrate edlulela kungqimba lwe-epitaxial phakathi nenqubo yokukhula kwe-epitaxial, imithetho yokudluliselwa nokuguqulwa kwamaphutha kusixhumi esibonakalayo esiphakathi kwe-substrate ne-epitaxial layer, kanye nendlela ye-nucleation yamaphutha iyisisekelo sokucacisa ukuhlobana phakathi ukukhubazeka kwe-substrate kanye nokukhubazeka kwesakhiwo se-epitaxial, okungaqondisa ngempumelelo ukuhlolwa kwe-substrate kanye nokwenza ngcono inqubo ye-epitaxial.
Amaphutha wei-silicon carbide epitaxial layersngokuyinhloko ihlukaniswe yaba izigaba ezimbili: crystal ukukhubazeka kanye surface morphology amaphutha. Ukukhubazeka kwekristalu, okuhlanganisa ukonakala kwamaphoyinti, ukugudluzwa kwezikulufu, ukonakala kwe-microtubule, ukugudluka konqenqema, njll., ikakhulukazi kusuka kumaphutha kuma-substrates e-SiC futhi asakazekela kungqimba lwe-epitaxial. Amaphutha e-Surface morphology angabonwa ngqo ngeso lenyama kusetshenziswa isibonakhulu futhi abe nezici ezijwayelekile ze-morphological. Amaphutha e-Surface morphology ikakhulukazi ahlanganisa: Ukuklwebha, ukukhubazeka kukanxantathu, ukukhubazeka kwe-Carrot, ukuwa, kanye ne-Particle, njengoba kuboniswe kuMfanekiso 4. Phakathi nenqubo ye-epitaxial, izinhlayiya zangaphandle, ukukhubazeka kwe-substrate, umonakalo ongaphezulu, kanye nokuphambuka kwenqubo ye-epitaxial konke kungase kuthinte ukuhamba kwesinyathelo sendawo. imodi yokukhula, okuholela ekulimaleni kwe-surface morphology.
Ithebula 1. Izimbangela zokwakheka kokukhubazeka okuvamile kwe-matrix kanye nokukhubazeka kokuma kwe-surface morphology ku-SiC epitaxial layers
Amaphuzu amaphutha
Amaphuzu angalungile akhiwa izikhala noma izikhala endaweni eyodwa ye-lattice noma amaphoyinti amaningana, futhi awanakho ukunwetshwa kwendawo. Amaphoyinti angahle avele kuyo yonke inqubo yokukhiqiza, ikakhulukazi ekufakweni kwe-ion. Kodwa-ke, kunzima ukuzibona, futhi ubudlelwano phakathi kokuguqulwa kweziphambeko zamaphuzu nezinye iziphambeko nakho kuyinkimbinkimbi kakhulu.
Amapayipi amancane (MP)
Amapayipi amancane ahlukanisa izikulufu ezingenalutho ezisakazeka eduze kwe-eksisi yokukhula, nge-Burgers vector <0001>. Ububanzi bama-microtube busuka kungxenyana ye-micron kuya kumashumi ama-microns. Ama-microtubes akhombisa izici ezingaphezulu ezinjengomgodi endaweni yamawafa e-SiC. Ngokuvamile, ukuminyana kwama-microtubes cishe ku-0.1~1cm-2 futhi kuyaqhubeka nokuncipha ekuqaphelweni kwekhwalithi yokukhiqizwa kwe-wafer.
I-Screw dislocations (TSD) kanye nokukhishwa komphetho (TED)
Ukususwa ku-SiC kuwumthombo oyinhloko wokonakala nokwehluleka kwedivayisi. Kokubili i-screw dislocation (TSD) kanye nokukhishwa konqenqemeni (TED) kuhambisana ne-eksisi yokukhula, nama-Burgers vectors we-<0001> kanye no-1/3<11–20>, ngokulandelanayo.
Kokubili ukukhishwa kwesikulufu (TSD) kanye nokukhishwa konqenqema (TED) kungasuka ku-substrate kuye endaweni eyiwafa futhi kulethe izici ezincane ezinjengomgodi (Umfanekiso 4b). Imvamisa, ukuminyana kokugudluzwa konqenqemeni cishe kuphindwe izikhathi eziyi-10 kunokwahlukaniswa ngezikulufu. Ukususwa kwezikulufu okunwetshiwe, okungukuthi, ukusuka ku-substrate kuya ku-epilayer, kungase futhi kuguquke kube okunye ukukhubazeka futhi kusakazeke eduze kwe-eksisi yokukhula. PhakathiI-SiC epitaxialukukhula, ukukhishwa kwezikulufu kuguqulwa kube amaphutha e-stacking (SF) noma ukukhubazeka kwe-carrot, kuyilapho ukuhlukaniswa konqenqema kuma-epilayers kuboniswa ukuthi kuguqulwe kusuka ekuhlukaniseni indiza ye-basal (BPDs) ezuzwe njengefa ku-substrate ngesikhathi sokukhula kwe-epitaxial.
Ukususwa kwendiza okuyisisekelo (BPD)
Itholakala endizeni ye-SiC basal, ene-Burgers vector engu-1/3 <11–20>. Ama-BPD awavamile ukuvela phezu kwamawafa e-SiC. Zivame ukugxila ku-substrate ngobuningi buka-1500 cm-2, kanti ukuminyana kwazo ku-epilayer kungama-10 cm-2 kuphela. Ukutholwa kwama-BPD kusetshenziswa i-photoluminescence (PL) kubonisa izici eziwumugqa, njengoba kuboniswe kuMfanekiso 4c. PhakathiI-SiC epitaxialukukhula, ama-BPD anwetshiwe angase aguqulwe abe amaphutha e-stacking (SF) noma i-edge dislocations (TED).
Amaphutha wokupakisha (SFs)
Amaphutha ekuhlelweni kokunqwabelanisa kwendiza ye-SiC basal. Amaphutha esitaki angavela kungqimba lwe-epitaxial ngokuthola ama-SF ku-substrate njengefa, noma ahlobane nesandiso nokuguqulwa kokugudluka kwendiza ye-basal (BPDs) kanye nokukhishwa kwesikulufu sentambo (TSDs). Ngokuvamile, ukuminyana kwama-SF kungaphansi kuka-1 cm-2, futhi abonisa isici esingunxantathu lapho etholwa kusetshenziswa i-PL, njengoba kuboniswe kuMfanekiso 4e. Kodwa-ke, izinhlobo ezahlukene zamaphutha okunqwabelanisa zingakhiwa ku-SiC, njengohlobo lwe-Shockley nohlobo luka-Frank, ngoba ngisho nenani elincane lokuphazamiseka kwamandla okunqwabelanisa phakathi kwezindiza kungaholela ekungalawuleni okukhulu ekulandeleni kokunqwabelanisa.
Ukuwa
Isici sokuwa ngokuyinhloko sisuka ekwehleni kwezinhlayiyana ezindongeni ezingenhla neseceleni zegumbi lokusabela ngesikhathi sokukhula, okungathuthukiswa ngokuthuthukisa inqubo yokugcinwa kwezikhathi ezithile kwezinto ezisebenzisekayo ze-reaction chamber graphite.
Isici esingunxantathu
Kuwukufakwa kwe-polytype ye-3C-SiC efinyelela ebusweni be-SiC epilayer eduze nokuqondisa kwendiza ye-basal, njengoba kuboniswe ku-Figure 4g. Ingase ikhiqizwe izinhlayiya eziwayo ebusweni be-SiC epilayer ngesikhathi sokukhula kwe-epitaxial. Izinhlayiya zifakwe ku-epilayer futhi ziphazamise inqubo yokukhula, okuholela ekufakweni kwe-polytype ye-3C-SiC, ebonisa izici ezibukhali ze-triangular surface nezinhlayiya ezitholakala kuma-vertices wesifunda esingunxantathu. Ucwaningo oluningi luphinde lwathi umsuka wokufakwa kwe-polytype ukuklwebheka phezulu, amapayipi amancane, kanye nemingcele engafanele yenqubo yokukhula.
Ukukhubazeka kwe-carrot
Isici sesanqante yinkinga yephutha enqwabelene eneziphetho ezimbili ezitholakala ezindizeni ze-TSD ne-SF basal crystal, eziqedwe ukuhlukaniswa kohlobo luka-Frank, futhi usayizi wesici sesanqante uhlobene nephutha le-prismatic stacking. Inhlanganisela yalezi zici yakha i-morphology engaphezulu yesici sesanqante, esibukeka njengesanqante esinobukhulu obungaphansi kuka-1 cm-2, njengoba kukhonjisiwe kuMfanekiso 4f. Ukukhubazeka kwekarothi kwakheka kalula ekuklwebeni kokupholisha, ama-TSD, noma ukukhubazeka kwe-substrate.
Ukuklwebheka
Ukuklwebheka kuwumonakalo owenziwe ngemishini ebusweni bezicwecwana ze-SiC ezakhiwe ngesikhathi sokukhiqiza, njengoba kukhonjisiwe kuMfanekiso 4h. Imihuzuko ku-substrate ye-SiC ingase iphazamise ukukhula kwe-epilayer, ikhiqize umugqa wokuhlukaniswa kwe-high-density dislocations ngaphakathi kwe-epilayer, noma imihuzuko ingase ibe isisekelo sokwakheka kokukhubazeka kwe-carrot. Ngakho-ke, kubalulekile ukupholisha kahle amawafa e-SiC ngoba lokhu kuklwebheka kungaba nomthelela omkhulu ekusebenzeni kwedivayisi uma kuvela endaweni esebenzayo yedivayisi.
Okunye ukukhubazeka kwe-surface morphology
I-step bunching iphutha elingaphezulu elakhiwe ngesikhathi senqubo yokukhula kwe-SiC epitaxial, ekhiqiza onxantathu aba-obtuse noma izici ze-trapezoidal ebusweni be-SiC epilayer. Ziningi ezinye iziphambeko ezingaphezulu, njengemigodi engaphezulu, amaqhubu namabala. Lezi zinkinga ngokuvamile zibangelwa izinqubo zokukhula ezingalungiselelwe kanye nokususwa okungaphelele komonakalo wokupholisha, okuthinta kabi ukusebenza kwedivayisi.
Isikhathi sokuthumela: Jun-05-2024