Kenyelletso ea Motheo ea SiC Epitaxial Growth Process

Epitaxial layer ke filimi e khethehileng ea kristale e le 'ngoe e hōlileng holim'a sephaphatha ka mokhoa oa ep·itaxial,' me substrate wafer le filimi ea epitaxial e bitsoa epitaxial wafer. Ka ho holisa silicon carbide epitaxial layer ho conductive silicon carbide substrate, silicon carbide homogeneous epitaxial wafer e ka lokisoa ho ea ho Schottky diode, MOSFETs, IGBTs le lisebelisoa tse ling tsa matla, tseo har'a tsona 4H-SiC substrate e sebelisoang haholo.

Ka lebaka la ts'ebetso e fapaneng ea tlhahiso ea sesebelisoa sa matla sa silicon carbide le sesebelisoa sa matla sa silicon sa setso, se ke ke sa etsoa ka kotloloho holim'a silicon carbide single crystal material. Lisebelisoa tse ling tsa boleng bo phahameng ba epitaxial li tlameha ho holisoa holim'a substrate e le 'ngoe ea kristale e tsamaisang,' me lisebelisoa tse fapaneng li tlameha ho etsoa holim'a epitaxial layer. Ka hona, boleng ba epitaxial layer bo na le tšusumetso e kholo ts'ebetsong ea sesebelisoa. Ntlafatso ea ts'ebetso ea lisebelisoa tse fapaneng tsa matla e boetse e beha litlhoko tse phahameng bakeng sa botenya ba epitaxial layer, mahloriso a doping le bofokoli.

FEIE. 1. Kamano pakeng tsa mahloriso a doping le botenya ba epitaxial layer ea sesebelisoa sa unipolar le "block voltage"

Mekhoa ea ho itokisa ea SIC epitaxial layer haholo-holo e kenyelletsa mokhoa oa ho hōla ha mouoane, khōlo ea mokelikeli oa epitaxial (LPE), kholo ea molek'hule epitaxial kgolo (MBE) le lik'hemik'hale tsa mouoane oa lik'hemik'hale (CVD). Hajoale, chemical vapor deposition (CVD) ke mokhoa o ka sehloohong o sebelisoang bakeng sa tlhahiso e kholo lifemeng.

FEIE. 2. Papiso ea mekhoa e ka sehloohong ea ho itokisa ea epitaxial layer

Karolong e ka thoko ea "off-axis {0001} e nang le Angle e itseng e sekamang, joalo ka ha ho bonts'itsoe ho Setšoantšo sa 2(b), boima ba sebaka sa mohato bo boholo, 'me boholo ba sebaka sa mohato bo nyane,' me kristale nucleation ha e bonolo ho e etsa. etsahala holim'a mohato, empa hangata ho etsahala sebakeng sa ho kopanya mohato. Tabeng ena, ho na le senotlolo se le seng feela sa nucleating. Ka hona, epitaxial layer e ka pheta ka ho phethahetseng taelo ea stacking ea substrate, kahoo e felisa bothata ba ho phela hammoho ka mefuta e mengata.

FEIE. 3. Setšoantšo sa 'mele oa mokhoa oa 4H-SiC oa ho laola mohato oa epitaxy

FEIE. 4. Maemo a bohlokoa bakeng sa kholo ea CVD ka mokhoa oa 4H-SiC o laoloang mohato oa epitaxy

FEIE. 5. Papiso ea litekanyetso tsa kgolo tlas'a mehloli e fapaneng ea silicon ho 4H-SiC epitaxy

Hajoale, theknoloji ea silicon carbide epitaxy e batla e holile ka har'a lisebelisoa tse tlase le tse mahareng (joalo ka lisebelisoa tsa 1200 volt). Botenya ba botenya, ho tšoana ha mahloriso a doping le kabo ea sekoli ea lera la epitaxial li ka fihla boemong bo batlang bo le botle, bo ka fihlelang litlhoko tsa matla a mahareng le a tlase a SBD (Schottky diode), MOS (metal oxide semiconductor field effect transistor), JBS ( junction diode) le lisebelisoa tse ling.

Leha ho le joalo, tšimong ea khatello e phahameng, li-wafers tsa epitaxial li ntse li hloka ho hlōla mathata a mangata. Ka mohlala, bakeng sa lisebelisoa tse hlokang ho mamella li-volts tse 10,000, botenya ba epitaxial layer bo lokela ho ba hoo e ka bang 100μm. Ha ho bapisoa le lisebelisoa tsa motlakase o tlase, botenya ba sekhahla sa epitaxial le ho ts'oana ha mohopolo oa doping li fapane haholo, haholo-holo ho ts'oana ha mohopolo oa doping. Ka nako e ts'oanang, sekoli sa kgutlotharo karolong ea epitaxial le eona e tla senya ts'ebetso ea kakaretso ea sesebelisoa. Lits'ebetsong tse nang le matla a phahameng, mefuta ea lisebelisoa e atisa ho sebelisa lisebelisoa tsa ho ferekana kelellong, tse hlokang bophelo ba batho ba fokolang haholo ka har'a epitaxial layer, kahoo ts'ebetso e hloka ho ntlafatsoa ho ntlafatsa bophelo ba batho ba fokolang.

Hajoale, epitaxy ea lapeng e boholo ba lisenthimithara tse 4 le lisenthimithara tse 6, 'me karolo ea boholo bo boholo ba silicon carbide epitaxy e ntse e eketseha selemo le selemo. Boholo ba silicon carbide epitaxial sheet bo fokotsoa haholo ke boholo ba silicon carbide substrate. Hajoale, 6-inch silicon carbide substrate e se e rekisitsoe, kahoo silicon carbide epitaxial butle-butle e fetoha ho tloha ho lisenthimithara tse 4 ho isa ho tse 6. Ka ntlafatso e tsoelang pele ea theknoloji ea ho lokisa silicon carbide substrate le katoloso ea bokhoni, theko ea silicon carbide substrate e ntse e fokotseha butle-butle. Sebopeho sa theko ea letlapa la epitaxial, substrate e ikarabella ho feta 50% ea litšenyehelo, kahoo ka ho theoha ha theko ea substrate, theko ea silicon carbide epitaxial sheet e boetse e lebelletsoe ho fokotseha.