Lalacewar triangular
Lalacewar yanayi na uku shine mafi munin lahani a cikin sinadarai na epitaxial na SiC. Yawancin rahotannin wallafe-wallafen sun nuna cewa samuwar lahani na triangular yana da alaƙa da nau'in crystal na 3C. Duk da haka, saboda nau'o'in girma daban-daban, ilimin halittar jiki na yawancin lahani na triangular a saman Layer epitaxial ya bambanta sosai. Ana iya raba shi kusan zuwa nau'ikan masu zuwa:
(1) Akwai lahani masu ma'ana guda uku masu manyan barbashi a sama
Irin wannan lahani na triangular yana da babban barbashi mai siffar zobe a sama, wanda zai iya faruwa ta hanyar faɗuwar abubuwa yayin aikin girma. Za'a iya lura da ƙaramin yanki mai kusurwa uku tare da ƙaƙƙarfan wuri zuwa ƙasa daga wannan gefen. Wannan shi ne saboda gaskiyar cewa a lokacin tsarin epitaxial, nau'i-nau'i na 3C-SiC daban-daban suna samuwa a jere a cikin yanki na triangular, wanda Layer na farko ya ƙare a cikin haɗin gwiwa kuma yana girma ta hanyar 4H-SiC mataki na gudana. Kamar yadda kauri na epitaxial Layer ya karu, Layer na biyu na 3C polytype nucleates kuma yana girma a cikin ƙananan ramukan triangular, amma matakin girma na 4H bai cika yankin 3C polytype gaba daya ba, yana yin yankin tsagi mai siffar V na 3C-SiC har yanzu a fili. bayyane
(2) Akwai ƙananan barbashi a sama da lahani na triangular tare da m surface
Barbashi da ke gefen wannan nau'in lahani na triangular sun fi ƙanƙanta, kamar yadda aka nuna a hoto 4.2. Kuma yawancin yankin triangular an rufe shi ta hanyar kwararar mataki na 4H-SiC, wato, gabaɗayan Layer na 3C-SiC an lulluɓe shi a ƙarƙashin Layer 4H-SiC. Matakan girma na 4H-SiC ne kawai za a iya gani a saman lahani na triangular, amma waɗannan matakan sun fi girma fiye da matakan girma na 4H na al'ada.
(3) Lalacewar triangular tare da santsi
Wannan nau'in lahani na triangular yana da santsin yanayin halitta, kamar yadda aka nuna a hoto 4.3. Don irin wannan lahani na triangular, 3C-SiC Layer an rufe shi ta hanyar kwararar 4H-SiC, kuma nau'in crystal na 4H akan saman yana girma mafi kyau da santsi.
Lalacewar rami na Epitaxial
Ramin Epitaxial (Ramuka) ɗaya ne daga cikin lahani na zahiri da aka fi sani da shi, kuma ana nuna yanayin halittar su na zahiri da tsarin tsarin su a cikin Hoto 4.4. Wurin da ke cikin ramukan lalata (TD) da aka lura da shi bayan KOH etching a bayan na'urar yana da cikakkiyar ma'ana tare da wurin da ke cikin ramukan epitaxial kafin shirye-shiryen na'urar, yana nuna cewa samuwar lahani na ramin epitaxial yana da alaƙa da ƙaddamar da zaren.
lahani karas
Lalacewar karas wata lahani ce ta kowa a cikin 4H-SiC epitaxial layers, kuma ana nuna yanayin halittar su a cikin Hoto 4.5. An ba da rahoton cewa an samu lahanin karas ta hanyar mahadar Franconian da kurakuran tari na prismatic da ke kan jirgin basal da aka haɗa ta hanyar tarwatsewa-kamar mataki. An kuma bayar da rahoton cewa samuwar lahani na karas yana da alaƙa da TSD a cikin substrate. Tsuchida H. et al. gano cewa yawan lahani na karas a cikin epitaxial Layer ya yi daidai da yawa na TSD a cikin substrate. Kuma ta hanyar kwatanta hotunan yanayin halittar jiki kafin da kuma bayan ci gaban epitaxial, duk lahani na karas da aka lura za a iya samun dacewa da TSD a cikin substrate. Wu H. et al. yayi amfani da yanayin gwajin watsawa na Raman don gano cewa lahanin karas bai ƙunshi nau'in crystal na 3C ba, amma kawai nau'in 4H-SiC.
Tasirin lahani na triangular akan halayen na'urar MOSFET
Hoto 4.7 shi ne kididdigar kididdiga ta rarraba halaye guda biyar na na'urar da ke dauke da lahani na uku. Layin shuɗi mai dige-dige shine layin rarraba don ɓarna halayyar na'ura, kuma jajayen layin ja shine layin rarraba don gazawar na'urar. Don gazawar na'urar, lahani na triangular yana da babban tasiri, kuma ƙimar gazawar ya fi 93%. Ana danganta wannan musamman ga tasirin lahani na triangular akan jujjuyawar na'urori. Har zuwa kashi 93% na na'urorin da ke ɗauke da lahani mai kusurwa uku sun ƙaru sosai. Bugu da ƙari, lahani na triangular shima yana da tasiri mai tsanani akan halayen ɗigon ƙofar, tare da raguwar ƙimar 60%. Kamar yadda aka nuna a cikin Tebu 4.2, don lalata wutar lantarki na kofa da lalata halayen diode, tasirin lahani na triangular yana da ƙananan, kuma raguwar raguwa shine 26% da 33% bi da bi. Dangane da haifar da karuwa a kan juriya, tasirin lahani na triangular yana da rauni, kuma raguwar raguwa yana kusan 33%.
Tasirin lahani na ramin epitaxial akan halayen na'urar MOSFET
Hoto na 4.8 shine kididdigar kididdiga ta rarraba halaye biyar na na'urar da ke dauke da lahani na ramin epitaxial. Layin shuɗi mai dige-dige shine layin rarraba don ɓarna halayyar na'ura, kuma jajayen layin ja shine layin rarraba don gazawar na'urar. Ana iya gani daga wannan cewa adadin na'urorin da ke dauke da lahani na epitaxial a cikin samfurin SiC MOSFET yana daidai da adadin na'urorin da ke dauke da lahani na triangular. Tasirin lahani na ramin epitaxial akan halayen na'ura ya bambanta da na lahani na triangular. Dangane da gazawar na'urar, ƙarancin gazawar na'urorin da ke ɗauke da lahani na ramin epitaxial shine kawai 47%. Idan aka kwatanta da lahani na triangular, tasirin lahani na ramin epitaxial akan jujjuyawar halaye da halayen ɗigon ƙofa na na'urar yana da rauni sosai, tare da raguwar ƙimar 53% da 38% bi da bi, kamar yadda aka nuna a cikin Table 4.3. A gefe guda, tasirin lahani na ramin epitaxial akan halayen ƙarfin wuta na bakin kofa, halayen tafiyar da diode jiki da juriya ya fi na lahani na triangular, tare da raguwar raguwa ya kai 38%.
Gabaɗaya, lahani guda biyu, wato triangles da ramukan epitaxial, suna da tasiri mai mahimmanci akan gazawa da lalata halayen na'urorin SiC MOSFET. Kasancewar lahani na triangular shine mafi muni, tare da gazawar adadin da ya kai 93%, galibi yana bayyana a matsayin babban haɓakar juzu'in na'urar. Na'urorin da ke ɗauke da lahani na ramin epitaxial suna da ƙarancin gazawar kashi 47%. Koyaya, lahani na rami na epitaxial yana da babban tasiri akan ƙarfin ƙarfin kofa na na'urar, halayen tafiyar da diode na jiki da juriya fiye da lahani mai kusurwa uku.
Lokacin aikawa: Afrilu-16-2024