Low Carbon n-GaN Drift Layers for Vertical Power Electronic Devices

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dc.contributor.authorCarlson, Eric Paulen
dc.contributor.committeechairGuido, Louis J.en
dc.contributor.committeememberLu, Guo Quanen
dc.contributor.committeememberSuchicital, Carlos T. A.en
dc.contributor.committeememberReynolds, William T.en
dc.contributor.committeememberNgo, Khai D.en
dc.contributor.departmentMaterials Science and Engineeringen
dc.date.accessioned2023-07-15T08:00:43Zen
dc.date.available2023-07-15T08:00:43Zen
dc.date.issued2023-07-14en
dc.description.abstractGaN holds significant potential as a material for vertical p-n diodes, enabling the realization of devices with reverse breakdown voltages of 5 kV or higher. Carbon serves as the primary compensating dopant in the growth process, incorporated into GaN during metalorganic chemical vapor deposition (MOCVD) growth. The level of carbon incorporation depends on several factors, including growth rate, ammonia flow, temperature, pressure, and trimethylgallium (TMGa) flow. Through guided empirical modeling, it was demonstrated that the carbon incorporation in GaN growth could be predicted using a single parameter based on the ratio of ammonia flow to the growth rate. This model accurately predicts carbon concentrations ranging from 1x1017 to 5x1014 cm-3 while allowing for maximized growth rates. Other extrinsic dopants have either been reduced below the threshold of consideration or modeled using similar single-parameter relationships. By identifying the dominant extrinsic dopants and accounting for them, an intrinsic defect with a concentration of 2.2x1015 cm-3 was identified. By combining these relationships, growth conditions for n-GaN were optimized, resulting in electron concentrations as low as 1x1015 cm-3. Leveraging these techniques, p-n diodes were grown, achieving a reverse breakdown voltage as high as 3.1 kV.en
dc.description.abstractgeneralPower electronic devices based on vertical GaN have the potential to revolutionize applications such as electric vehicles, solar charging systems, and the smart grid. However, there are significant materials challenges that need to be addressed in order to realize these devices. They must be extremely pure and extremely thick. Unfortunately, the primary source of these materials also contains carbon, which can negatively impact purity. To overcome this challenge, an empirical model for the growth process has been developed. This model enables independent control over the carbon source and the removal of carbon, using a single parameter. By leveraging this model, it becomes possible to optimize the trade-off between high purity, high growth rates, and ideal electronic properties. Using these techniques, devices were grown with next-generation levels of performance at minimal time and cost.en
dc.description.degreeDoctor of Philosophyen
dc.format.mediumETDen
dc.identifier.othervt_gsexam:37926en
dc.identifier.urihttp://hdl.handle.net/10919/115781en
dc.language.isoenen
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectGallium Nitrideen
dc.subjectPower Electronicsen
dc.subjectMOCVDen
dc.subjectepitaxial growthen
dc.subjectIII-V Semiconductorsen
dc.subjectpn diodeen
dc.subjectcarbon impuritiesen
dc.subjectpoint defectsen
dc.titleLow Carbon n-GaN Drift Layers for Vertical Power Electronic Devicesen
dc.typeDissertationen
thesis.degree.disciplineMaterials Science and Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.nameDoctor of Philosophyen

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