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Design Optimization...
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Elahipanah, Hossein,1982-KTH,Elektronik,Electronics
(author)
Design Optimization and Realization of 4H-SiC Bipolar Junction Transistors
Publisher, publication year, extent ...
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Stockholm :KTH Royal Institute of Technology,2017
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116 s.
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electronicrdacarrier
Numbers
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LIBRIS-ID:oai:DiVA.org:kth-211659
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ISBN:9789177294818
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https://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-211659URI
Supplementary language notes
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Language:English
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Summary in:English
Part of subdatabase
Classification
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Subject category:vet swepub-contenttype
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Subject category:dok swepub-publicationtype
Series
Notes
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QC 20170810
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4H-SiC-based bipolar junction transistors (BJTs) are attractive devices for high-voltage and high-temperature operations due to their high current capability, low specific on-resistance, and process simplicity. To extend the potential of SiC BJTs to power electronic industrial applications, it is essential to realize high-efficient devices with high-current and low-loss by a reliable and wafer-scale fabrication process. In this thesis, we focus on the improvement of the 4H-SiC BJT performance, including the device optimization and process development.To optimize the 4H-SiC BJT design, a comprehensive study in terms of cell geometries, device scaling, and device layout is performed. The hexagon-cell geometry shows 42% higher current density and 21% lower specific on-resistance at a given maximum current gain compared to the interdigitated finger design. Also, a layout design, called intertwined, is used for 100% usage of the conducting area. A higher current is achieved by saving the inactive portion of the conducting area. Different multi-step etched edge termination techniques with an efficiency of >92% are realized.Regarding the process development, an improved surface passivation is used to reduce the surface recombination and improve the maximum current gain of 4H-SiC BJTs. Moreover, wafer-scale lift-off-free processes for the n- and p-Ohmic contact technologies to 4H-SiC are successfully developed. Both Ohmic metal technologies are based on a self-aligned Ni-silicide (Ni-SALICIDE) process.Regarding the device characterization, a maximum current gain of 40, a specific on-resistance of 20 mΩ·cm2, and a maximum breakdown voltage of 5.85 kV for the 4H-SiC BJTs are measured. By employing the enhanced surface passivation, a maximum current gain of 139 and a specific on-resistance of 579 mΩ·cm2 at the current density of 89 A/cm2 for the 15-kV class BJTs are obtained. Moreover, low-voltage 4H-SiC lateral BJTs and Darlington pair with output current of 1−15 A for high-temperature operations up to 500 °C were fabricated.This thesis focuses on the improvement of the 4H-SiC BJT performance in terms of the device optimization and process development for high-voltage and high-temperature applications. The epilayer design and the device structure and topology are optimized to realize high-efficient BJTs. Also, wafer-scale fabrication process steps are developed to enable realization of high-current devices for the real applications.
Subject headings and genre
Added entries (persons, corporate bodies, meetings, titles ...)
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Östling, Mikael,ProfessorKTH,Elektronik
(thesis advisor)
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Zetterling, Carl-Mikael,ProfessorKTH,Elektronik
(thesis advisor)
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Hallèn, Anders
(thesis advisor)
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Schöner, Adolf
(thesis advisor)
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Kimoto, Tsunenobu
(opponent)
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KTHElektronik
(creator_code:org_t)
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