Indraneel Sanyal, Arpit Nandi, David Cherns, Martin Kuball
{"title":"通过金属有机化学气相沉积实现 Ga2O3 异质外延和材料生长的热力学","authors":"Indraneel Sanyal, Arpit Nandi, David Cherns, Martin Kuball","doi":"10.1021/acsaelm.4c00535","DOIUrl":null,"url":null,"abstract":"Heteroepitaxy of gallium oxide (Ga<sub>2</sub>O<sub>3</sub>) is gaining popularity to address the absence of p-type doping, limited thermal conductivity of Ga<sub>2</sub>O<sub>3</sub> epilayers, and toward realizing high-quality p-n heterojunction. During the growth of β-Ga<sub>2</sub>O<sub>3</sub> on 4H-SiC (0001) substrates using metal–organic chemical vapor deposition, we observed formation of incomplete, misoriented particles when the layer was grown at a temperature between 650 °C and 750 °C. We propose a thermodynamic model for Ga<sub>2</sub>O<sub>3</sub> heteroepitaxy on foreign substrates which shows that the energy cost of growing β-Ga<sub>2</sub>O<sub>3</sub> on 4H-SiC is slightly lower as compared to sapphire substrates, suggesting similar high-temperature growth as sapphire, typically in the range of 850 °C–950 °C, that can be used for the growth of β-Ga<sub>2</sub>O<sub>3</sub> on SiC. A two-step modified growth method was developed where the nucleation layer was grown at 750 °C followed by a buffer layer grown at various temperatures from 920 °C to 950 °C. 2θ–ω scan of X-ray diffraction (XRD) and transmission electron microscope images confirm the β-polymorph of Ga<sub>2</sub>O<sub>3</sub> with dominant peaks in the (−201) direction. The buffer layer grown at 950 °C using a “ramp-growth” technique exhibits root-mean-square surface roughness of 3 nm and full width of half maxima of XRD rocking curve as low as 0.79°, comparable to the most mature β-Ga<sub>2</sub>O<sub>3</sub> heteroepitaxy on sapphire, as predicted by the thermodynamic model. Finally, the interface energy of an average Ga<sub>2</sub>O<sub>3</sub> island grown on 4H-SiC is calculated to be 0.2 J/m<sup>2</sup> from the cross-section scanning transmission electron microscope image, following the Wulff-Kaishew theorem of the equilibrium island shape.","PeriodicalId":3,"journal":{"name":"ACS Applied Electronic Materials","volume":null,"pages":null},"PeriodicalIF":4.3000,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Thermodynamics of Ga2O3 Heteroepitaxy and Material Growth Via Metal Organic Chemical Vapor Deposition\",\"authors\":\"Indraneel Sanyal, Arpit Nandi, David Cherns, Martin Kuball\",\"doi\":\"10.1021/acsaelm.4c00535\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Heteroepitaxy of gallium oxide (Ga<sub>2</sub>O<sub>3</sub>) is gaining popularity to address the absence of p-type doping, limited thermal conductivity of Ga<sub>2</sub>O<sub>3</sub> epilayers, and toward realizing high-quality p-n heterojunction. During the growth of β-Ga<sub>2</sub>O<sub>3</sub> on 4H-SiC (0001) substrates using metal–organic chemical vapor deposition, we observed formation of incomplete, misoriented particles when the layer was grown at a temperature between 650 °C and 750 °C. We propose a thermodynamic model for Ga<sub>2</sub>O<sub>3</sub> heteroepitaxy on foreign substrates which shows that the energy cost of growing β-Ga<sub>2</sub>O<sub>3</sub> on 4H-SiC is slightly lower as compared to sapphire substrates, suggesting similar high-temperature growth as sapphire, typically in the range of 850 °C–950 °C, that can be used for the growth of β-Ga<sub>2</sub>O<sub>3</sub> on SiC. A two-step modified growth method was developed where the nucleation layer was grown at 750 °C followed by a buffer layer grown at various temperatures from 920 °C to 950 °C. 2θ–ω scan of X-ray diffraction (XRD) and transmission electron microscope images confirm the β-polymorph of Ga<sub>2</sub>O<sub>3</sub> with dominant peaks in the (−201) direction. The buffer layer grown at 950 °C using a “ramp-growth” technique exhibits root-mean-square surface roughness of 3 nm and full width of half maxima of XRD rocking curve as low as 0.79°, comparable to the most mature β-Ga<sub>2</sub>O<sub>3</sub> heteroepitaxy on sapphire, as predicted by the thermodynamic model. Finally, the interface energy of an average Ga<sub>2</sub>O<sub>3</sub> island grown on 4H-SiC is calculated to be 0.2 J/m<sup>2</sup> from the cross-section scanning transmission electron microscope image, following the Wulff-Kaishew theorem of the equilibrium island shape.\",\"PeriodicalId\":3,\"journal\":{\"name\":\"ACS Applied Electronic Materials\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":4.3000,\"publicationDate\":\"2024-06-21\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"ACS Applied Electronic Materials\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://doi.org/10.1021/acsaelm.4c00535\",\"RegionNum\":3,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ENGINEERING, ELECTRICAL & ELECTRONIC\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Applied Electronic Materials","FirstCategoryId":"88","ListUrlMain":"https://doi.org/10.1021/acsaelm.4c00535","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, ELECTRICAL & ELECTRONIC","Score":null,"Total":0}
Thermodynamics of Ga2O3 Heteroepitaxy and Material Growth Via Metal Organic Chemical Vapor Deposition
Heteroepitaxy of gallium oxide (Ga2O3) is gaining popularity to address the absence of p-type doping, limited thermal conductivity of Ga2O3 epilayers, and toward realizing high-quality p-n heterojunction. During the growth of β-Ga2O3 on 4H-SiC (0001) substrates using metal–organic chemical vapor deposition, we observed formation of incomplete, misoriented particles when the layer was grown at a temperature between 650 °C and 750 °C. We propose a thermodynamic model for Ga2O3 heteroepitaxy on foreign substrates which shows that the energy cost of growing β-Ga2O3 on 4H-SiC is slightly lower as compared to sapphire substrates, suggesting similar high-temperature growth as sapphire, typically in the range of 850 °C–950 °C, that can be used for the growth of β-Ga2O3 on SiC. A two-step modified growth method was developed where the nucleation layer was grown at 750 °C followed by a buffer layer grown at various temperatures from 920 °C to 950 °C. 2θ–ω scan of X-ray diffraction (XRD) and transmission electron microscope images confirm the β-polymorph of Ga2O3 with dominant peaks in the (−201) direction. The buffer layer grown at 950 °C using a “ramp-growth” technique exhibits root-mean-square surface roughness of 3 nm and full width of half maxima of XRD rocking curve as low as 0.79°, comparable to the most mature β-Ga2O3 heteroepitaxy on sapphire, as predicted by the thermodynamic model. Finally, the interface energy of an average Ga2O3 island grown on 4H-SiC is calculated to be 0.2 J/m2 from the cross-section scanning transmission electron microscope image, following the Wulff-Kaishew theorem of the equilibrium island shape.