Ndeapi kukanganisa kwesilicon carbide epitaxial layer

Iyo yakakosha tekinoroji yekukura kweSiC epitaxialzvinhu zvekutanga hurema hwekudzora tekinoroji, kunyanya yehurema hwekudzora tekinoroji iyo inotarirwa kutadza kwechishandiso kana kukanganisa kwekuvimbika. Kuongorora kwemaitiro e substrate defects inosvika mu epitaxial layer panguva ye epitaxial growth process, kutapurirana uye kushandura mitemo yezvakaremara painterface pakati pe substrate ne epitaxial layer, uye nucleation mechanism yekuremara ndiyo hwaro hwekujekesa kuwirirana pakati. substrate defects uye epitaxial structural defects, iyo inogona kunyatso kutungamira substrate kuongorora uye epitaxial process optimization.

Kukanganisa kwesilicon carbide epitaxial layersanonyanya kukamurwa kuita mapoka maviri: crystal defects uye surface morphology defects. Kuremara kweCrystal, kunosanganisira kuremara kwepoinzi, screw dislocation, microtubule defects, edge dislocations, nezvimwewo, zvinonyanya kubva pakukanganisa paSiC substrates uye zvinopararira muepitaxial layer. Surface morphology defects inogona kutariswa zvakananga neziso rakashama uchishandisa maikorosikopu uye kuve neyakajairika morphological maitiro. Surface morphology defects inonyanya kusanganisira: Scratch, Triangular defect, Carrot defect, Downfall, uye Particle, sezvinoratidzwa mumufananidzo 4. Munguva ye epitaxial process, kunze kwenyika, substrate defects, kukuvara kwepamusoro, uye epitaxial process deviations zvese zvinogona kukanganisa kuyerera kwenzvimbo. Kukura kwemaitiro, zvichikonzera kukanganisa kwepamusoro morphology.

Tafura 1.Zvinokonzera yekugadzirwa kweakajairwa matrix kukanganisa uye pamusoro morphology kukanganisa muSiC epitaxial layers.

Point defects

Mapoinzi akaremara anoumbwa neavacancies kana magap pane imwe lattice point kana akati wandei ma lattice point, uye haana nzvimbo yekuwedzera. Mapoinzi kukanganisa kunogona kuitika mune yega yega maitiro ekugadzira, kunyanya mukuisirwa ion. Nekudaro, iwo akaoma kuona, uye hukama pakati pekushandurwa kwemapoinzi kuremara uye humwe hurema hwakaomawo.

Micropipes (MP)

Micropipes ihollow screw dislocations inopararira pamwe neaxis yekukura, ine Burgers vector <0001>. Iyo dhayamita yemicrotubes inotangira kubva pachidimbu chemicron kusvika kumakumi emakironi. Microtubes inoratidza hombe-yakafanana nepamusoro maficha ari pamusoro peSiC wafers. Kazhinji, huwandu hwemamicrotubes hunosvika 0.1 ~ 1cm-2 uye hunoramba huchidzikira mukutengesa wafer yemhando yekutarisa.

Screw dislocations (TSD) uye edge dislocations (TED)

Dislocations muSiC ndiyo sosi huru yekushatisa mudziyo uye kutadza. Ese ari maviri screw dislocations (TSD) uye edge dislocations (TED) inomhanya ichitevedza axis yekukura, ine maBurger vectors e <0001> uye 1/3 <11-20>, zvichiteerana.

Ese ari maviri screw dislocations (TSD) uye edge dislocations (TED) anogona kubva pa substrate kuenda kune wafer pamusoro uye kuunza diki gomba-sepamusoro maficha (Mufananidzo 4b). Kazhinji, density ye edge dislocations ingangoita ka10 iyo ye screw dislocation. Yakawedzerwa screw dislocations, kureva, kubva pa substrate kuenda kune epilayer, inogona zvakare kushandura kuita kumwe kukanganisa uye kuparadzira pamwe neakisi yekukura. PanguvaSiC epitaxialkukura, screw dislocations inoshandurwa kuita stacking zvikanganiso (SF) kana karoti defects, nepo edge dislocations ari epilayers anoratidzwa kushandurwa kubva basal ndege dislocations (BPDs) nhaka kubva substrate panguva epitaxial kukura.

Basic plane dislocation (BPD)

Iri paSiC basal ndege, ine Burgers vector ye1/3 <11-20>. BPDs haiwanzo kuoneka pamusoro peSiC wafers. Vanowanzoiswa pa substrate ine density ye 1500 cm-2, nepo density yavo mu epilayer inenge 10 cm-2 chete. Kuonekwa kweBPDs uchishandisa photoluminescence (PL) inoratidza mutsara maficha, sezvakaratidzwa mumufananidzo 4c. PanguvaSiC epitaxialkukura, BPD yakawedzerwa inogona kushandurwa kuita zvikanganiso zvakaturikidzana (SF) kana edge dislocation (TED).

Stacking kukanganisa (SFs)

Kukanganisa mukutevedzana kwekutevedzana kweSiC basal ndege. Kukanganisa kwakaturikidzana kunogona kuoneka mu epitaxial layer nekugara nhaka maSF mu substrate, kana kuve nehukama nekuwedzera uye shanduko yebasal plane dislocations (BPDs) uye threading screw dislocations (TSDs). Kazhinji, kuwanda kweSFs kuri pasi pe1 cm-2, uye vanoratidza chimiro chetriangular kana vakaonekwa vachishandisa PL, sezvakaratidzwa mumufananidzo 4e. Nekudaro, marudzi akasiyana-siyana ezvikanganiso zvekututira anogona kuumbwa muSiC, senge Shockley mhando uye Frank mhando, nekuti kunyangwe diki diki rekuisa simba kusagadzikana pakati pendege rinogona kutungamirira kune kusarongeka kukuru mukutevedzana kwekurongedza.

Kudonha

Kukanganisa kwekudonha kunonyanya kutangira kubva kudonho remukati kumadziro ekumusoro uye epadivi ekamuri yekupindura panguva yekukura, iyo inogona kuvandudzwa nekugadzirisa iyo periodic kuchengetedza maitiro eiyo reaction chamber graphite consumables.

Triangular defect

Iyo 3C-SiC polytype inclusion iyo inotambanudzira kusvika pamusoro peSiC epilayer parutivi rwebasal plane direction, sezvakaratidzwa muFigure 4g. Inogona kugadzirwa nezvikamu zvinodonha pamusoro peSiC epilayer panguva yekukura kwe epitaxial. Izvo zvimedu zvakabatanidzwa mu epilayer uye zvinokanganisa maitiro ekukura, zvichiita kuti 3C-SiC polytype inclusions, iyo inoratidzira inopinza-angled triangular surface features nezvikamu zviri pa vertices ye triangular region. Zvidzidzo zvakawanda zvakare zvakati kwakabva polytype inclusions kune pamusoro pezvikwambo, micropipes, uye zvisina kufanira maparamita ekukura maitiro.

Karoti kuremara

Karoti kuremara imhata yekukanganisa ine migumo miviri iri paTSD uye SF basal crystal ndege, yakamiswa neFrank-type dislocation, uye saizi yehurema hwekaroti inoenderana neprismatic stacking kukanganisa. Iko kusanganiswa kwezvinhu izvi kunoumba pamusoro morphology yekaroti defect, iyo inoratidzika seyakaroti chimiro ine density isingasviki 1 cm-2, sezvakaratidzwa muFigure 4f. Karoti hurema hunoumbwa zviri nyore pakukwenenzverwa kwekukwenya, TSDs, kana substrate kukanganisa.

Makwara

Zvikwenya kukuvadzwa kwemagetsi pamusoro peSiC wafers akaumbwa panguva yekugadzira, sezvakaratidzwa mumufananidzo 4h. Zvisungo paSiC substrate zvinogona kukanganisa kukura kweiyo epilayer, kubudisa mutsara wepamusoro-density dislocations mukati me epilayer, kana kuputika kunogona kuva hwaro hwekuumbwa kwekuremara kwekaroti. Naizvozvo, zvakakosha kukwenenzvera maSiC wafers nekuti aya makwara anogona kuve nekukanganisa kukuru pakuita kwechishandiso kana achinge aonekwa munzvimbo inoshanda mudziyo.

Zvimwe zvinokanganisa morphology

Step bunching chirema chepamusoro chakaumbwa panguva yeSiC epitaxial kukura process, iyo inoburitsa obtuse matriangles kana trapezoidal maficha ari pamusoro peSiC epilayer. Kune zvimwe zvakawanda zvinokanganisa pamusoro, senge makomba epamusoro, mabumps uye mavara. Kukanganisa uku kunowanzo kukonzerwa nemaitiro asina kunaka ekukura uye kubviswa kusina kukwana kwekukuvadza kwekuporeshera, izvo zvinokanganisa kuita kwechishandiso.