ʻO ka ʻenehana ulu ʻokiʻoki a me ka ulu ʻana o ka epitaxial-Ⅱ

2. Ka ulu ʻana o ka ʻili lahilahi epitaxial

Hāʻawi ka substrate i kahi papa kākoʻo kino a i ʻole ka papa alakaʻi no nā mea mana Ga2O3. ʻO ka papa koʻikoʻi aʻe ʻo ia ka papa kahawai a i ʻole ka papa epitaxial i hoʻohana ʻia no ke kū'ē ʻana i ka voltage a me ka lawe ʻana i ka mea lawe. I mea e hoʻonui ai i ka voltage breakdown a hōʻemi i ke kū'ē ʻana i ka conduction, ʻo ka mānoanoa hiki ke hoʻomalu ʻia a me ka hoʻohuihui doping, a me ka maikaʻi o ka mea kūpono, kekahi mau mea mua. Hoʻokomo pinepine ʻia nā papa epitaxial Ga2O3 kiʻekiʻe me ka hoʻohana ʻana i ka molecular beam epitaxy (MBE), metal organic chemical vapor deposition (MOCVD), halide vapor deposition (HVPE), pulsed laser deposition (PLD), a me nā ʻano hana deposition e pili ana i ka fog CVD.

Papa 2 Kekahi mau ʻenehana epitaxial ma ke ʻano he koho

2.1 Ke ʻano hana MBE

Ua kaulana ka ʻenehana MBE no kona hiki ke hoʻoulu i nā kiʻiʻoniʻoni β-Ga2O3 kiʻekiʻe, ʻaʻohe kīnā me ka doping ʻano-n hiki ke hoʻomalu ʻia ma muli o kona wahi vacuum ultra-kiʻekiʻe a me ka maʻemaʻe o nā mea. ʻO ka hopena, ua lilo ia i hoʻokahi o nā ʻenehana waiho ʻana o ka kiʻiʻoniʻoni lahilahi β-Ga2O3 i aʻo nui ʻia a hiki ke kūʻai ʻia. Eia kekahi, ua hoʻomākaukau maikaʻi ke ʻano MBE i kahi papa kiʻiʻoniʻoni lahilahi heterostructure β-(AlXGa1-X)2O3/Ga2O3 kiʻekiʻe, haʻahaʻa. Hiki iā MBE ke nānā i ke ʻano o ka ʻili a me ke ʻano o ka morphology i ka manawa maoli me ka pololei o ka papa atomika ma ka hoʻohana ʻana i ka reflection high energy electron diffraction (RHEED). Eia nō naʻe, ke kū nei nā kiʻiʻoniʻoni β-Ga2O3 i ulu ʻia me ka hoʻohana ʻana i ka ʻenehana MBE i nā pilikia he nui, e like me ka haʻahaʻa o ka ulu ʻana a me ka liʻiliʻi o ka nui o ka kiʻiʻoniʻoni. Ua ʻike ʻia ma ke aʻo ʻana aia ka nui o ka ulu ʻana ma ke ʻano o (010)>(001)>(−201)>(100). Ma lalo o nā kūlana waiwai iki o Ga o 650 a 750°C, hōʻike ʻo β-Ga2O3 (010) i ka ulu kūpono me kahi ʻili laumania a me ka wikiwiki o ka ulu ʻana. Ma ka hoʻohana ʻana i kēia ʻano hana, ua hoʻokō pono ʻia ka epitaxy β-Ga2O3 me ka RMS roughness o 0.1 nm. β-Ga2O3 Ma kahi kaiapuni waiwai o Ga, hōʻike ʻia nā kiʻiʻoniʻoni MBE i ulu ʻia ma nā mahana like ʻole ma ke kiʻi. Ua hana maikaʻi ʻo Novel Crystal Technology Inc. i nā wafers 10 × 15mm2 β-Ga2O3MBE i ka epitaxially. Hāʻawi lākou i nā substrates kristal hoʻokahi β-Ga2O3 kiʻekiʻe (010) me ka mānoanoa o 500 μm a me XRD FWHM ma lalo o 150 arc seconds. Ua hoʻopili ʻia ka substrate me Sn a i ʻole Fe. Loaʻa i ka substrate conductive Sn-doped kahi concentration doping o 1E18 a 9E18cm−3, ʻoiai ʻo ka substrate semi-insulating iron-doped he resistivity kiʻekiʻe ma mua o 10E10 Ω cm.

2.2 Ke ʻano hana MOCVD

Hoʻohana ʻo MOCVD i nā hui metala organik ma ke ʻano he mea mua e ulu ai nā ʻili lahilahi, a laila e hoʻokō ai i ka hana kalepa nui. I ka wā e ulu ai ʻo Ga2O3 me ka hoʻohana ʻana i ke ʻano MOCVD, hoʻohana pinepine ʻia ka trimethylgallium (TMGa), triethylgallium (TEGa) a me Ga (dipentyl glycol formate) ma ke ʻano he kumu Ga, ʻoiai ʻo H2O, O2 a i ʻole N2O e hoʻohana ʻia ma ke ʻano he kumu oxygen. ʻO ka ulu ʻana me ka hoʻohana ʻana i kēia ʻano hana e pono ai nā mahana kiʻekiʻe (>800°C). Loaʻa i kēia ʻenehana ka hiki ke hoʻokō i ka haʻahaʻa o ka lawe ʻana a me ka neʻe ʻana o nā electron wela kiʻekiʻe a haʻahaʻa, no laila he mea nui ia i ka hoʻokō ʻana i nā mea hana mana β-Ga2O3 kiʻekiʻe. Ke hoʻohālikelike ʻia me ke ʻano ulu MBE, loaʻa iā MOCVD ka pono o ka hoʻokō ʻana i nā helu ulu kiʻekiʻe loa o nā ʻili β-Ga2O3 ma muli o nā ʻano o ka ulu wela kiʻekiʻe a me nā hopena kemika.

Kiʻi 7 β-Ga2O3 (010) kiʻi AFM

Kiʻi 8 β-Ga2O3 ʻO ka pilina ma waena oμ a me ke kū'ē'ē pepa i ana ʻia e Hall a me ka mahana

2.3 Ke ʻano hana HVPE

He ʻenehana epitaxial makua ʻo HVPE a ua hoʻohana nui ʻia i ka ulu ʻana o ka epitaxial o nā semiconductors hui III-V. Ua ʻike ʻia ʻo HVPE no kona kumukūʻai hana haʻahaʻa, ka wikiwiki o ka ulu ʻana, a me ka mānoanoa o ke kiʻiʻoniʻoni kiʻekiʻe. Pono e hoʻomaopopo ʻia he hōʻike pinepine ka HVPEβ-Ga2O3 i ke ʻano o ka ʻili ʻino a me ka nui o nā kīnā o ka ʻili a me nā lua. No laila, pono nā kaʻina hana polishing kemika a me ka mechanical ma mua o ka hana ʻana i ka hāmeʻa. Hoʻohana pinepine ka ʻenehana HVPE no ka epitaxy β-Ga2O3 i ke kinoea GaCl a me O2 ma ke ʻano he precursors e hoʻolaha i ka hopena wela kiʻekiʻe o ka matrix (001) β-Ga2O3. Hōʻike ka Kiʻi 9 i ke kūlana o ka ʻili a me ka wikiwiki o ka ulu ʻana o ke kiʻiʻoniʻoni epitaxial ma ke ʻano he hana o ka mahana. I nā makahiki i hala iho nei, ua hoʻokō ʻo Novel Crystal Technology Inc. o Iapana i ka holomua kālepa koʻikoʻi ma HVPE homoepitaxial β-Ga2O3, me nā mānoanoa o ka papa epitaxial o 5 a 10 μm a me nā nui wafer o 2 a me 4 ʻīniha. Eia kekahi, ua komo pū nā wafers homoepitaxial HVPE β-Ga2O3 20 μm mānoanoa i hana ʻia e China Electronics Technology Group Corporation i ke kahua kūʻai.

Kiʻi 9 Hana HVPE β-Ga2O3

2.4 ʻAno hana PLD

Hoʻohana nui ʻia ka ʻenehana PLD e waiho i nā kiʻiʻoniʻoni oxide paʻakikī a me nā heterostructures. I ka wā o ke kaʻina hana ulu PLD, ua hoʻopili ʻia ka ikehu photon i ka mea i manaʻo ʻia ma o ke kaʻina hana hoʻokuʻu electron. I ka hoʻohālikelike ʻana me MBE, ua hoʻokumu ʻia nā ʻāpana kumu PLD e ka radiation laser me ka ikehu kiʻekiʻe loa (>100 eV) a ma hope iho ua waiho ʻia ma luna o kahi substrate i hoʻomehana ʻia. Eia nō naʻe, i ka wā o ke kaʻina hana ablation, e hoʻopilikia pololei kekahi mau ʻāpana ikehu kiʻekiʻe i ka ʻili o ka mea, e hana ana i nā hemahema kiko a pēlā e hōʻemi ai i ka maikaʻi o ke kiʻiʻoniʻoni. E like me ke ʻano MBE, hiki ke hoʻohana ʻia ʻo RHEED e nānā i ke ʻano o ka ʻili a me ke ʻano o ka mea i ka manawa maoli i ka wā o ke kaʻina hana waiho ʻana o PLD β-Ga2O3, e ʻae ana i nā mea noiʻi e loaʻa pololei ka ʻike ulu. Manaʻo ʻia ke ʻano PLD e ulu i nā kiʻiʻoniʻoni β-Ga2O3 conductive kiʻekiʻe, e lilo ia i hopena hoʻopili ohmic i hoʻomaikaʻi ʻia i nā mea mana Ga2O3.

Kiʻi 10 Kiʻi AFM o Si doped Ga2O3

2.5 Ke ʻano hana MIST-CVD

He ʻenehana ulu ʻili lahilahi maʻalahi a kūpono hoʻi ka MIST-CVD. Pili kēia ʻano CVD i ka hopena o ka pīpī ʻana i kahi precursor atomized ma luna o kahi substrate e hoʻokō ai i ka waiho ʻana o ka ʻili lahilahi. Eia nō naʻe, a hiki i kēia manawa, ʻaʻohe mau waiwai uila maikaʻi o Ga2O3 i ulu ʻia me ka hoʻohana ʻana i ka mist CVD, kahi e waiho ai i kahi nui no ka hoʻomaikaʻi a me ka hoʻonui ʻana i ka wā e hiki mai ana.