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Materials and Device Engineering for High Performance Beta-Gallium Oxide-based Electronics.pdf (3.5 MB)
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Abstract Header
Materials and Device Engineering for High Performance β-Ga2O3-based Electronics
Author Info
Xia, Zhanbo
ORCID® Identifier
http://orcid.org/0000-0002-6827-6893
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=osu1587688595358557
Abstract Details
Year and Degree
2020, Doctor of Philosophy, Ohio State University, Electrical and Computer Engineering.
Abstract
β-Ga
2
O
3
has recently attracted attention as an ultra-wide bandgap (4.7 eV) semiconductor that can be controllably doped, and grown directly from the melt in single crystal form. The ease of n-type doping with tetravalent cations, a wide variety of bulk single crystal and epitaxial film growth techniques have triggered worldwide interest in β-Ga
2
O
3
. The predicted breakdown electric field (6-8 MV/cm) is higher than that of GaN or SiC (~3 MV/cm), which when combined with electron mobility (predicted ~250 cm
2
/Vs) and electron velocity (1.2×10
7
cm/s) yields higher figures of merits than SiC and GaN devices. This thesis presents theoretical and experimental investigations of β-Ga
2
O
3
device designs to achieve high-performance RF and power electronics for future applications. The first part of the thesis analyzes the potential device advantages that can be derived from the fundamental β-Ga
2
O
3
material parameters (electron mobility, saturation velocity, and breakdown field). The theoretical β-Ga
2
O
3
device output power density is calculated and compared to GaN HEMTs to find the potential RF applications of β-Ga
2
O
3
devices. The potential of β-Ga
2
O
3
for power devices is also calculated and discussed. Through detailed 2-D device simulation, device design strategies for utilizing the high breakdown field and mitigating low electron mobility effects are proposed. The thesis then focuses on the experimental demonstration and progress on lateral β-Ga
2
O
3
device designs, including (AlGa)
2
O
3
/Ga
2
O
3
MODFETs and delta-doped MESFFETs. (AlGa)
2
O
3
/Ga
2
O
3
MODFET is one suitable device structure for high-performance β-Ga
2
O
3
electronics because of the 2-D electron gas (2DEG) channel with high electron mobility. The electrical properties of the grown film and the MODFET device characteristics are studied. MBE-grown Ohmic contact is developed for the (AlGa)
2
O
3
/Ga
2
O
3
MODFETs to improve their device performance. The high mobility 2DEG channel and low-resistance Ohmic contact enable the direct measurements of the electron saturation velocity of β-Ga
2
O
3
. The electron saturation velocity of 1.2x10
7
cm/s is obtained through two-terminal saturation current measurements and transit time analysis of the transistors, which confirms the potentials for β-Ga
2
O
3
RF applications. As the other suitable lateral device structure, β-Ga
2
O
3
delta-doped MESFFETs offer more design flexibility on high channel charge density than (AlGa)
2
O
3
/Ga
2
O
3
MODFETs. β-Ga
2
O
3
delta-doped MESFFETs with ultra-scaled gate lengths are demonstrated. The devices achieve a current gain cut-off frequency of 27 GHz, the highest reported to date, with a peak current density of 260 mA/mm. Regarding electric field management, BaTiO
3
/β-Ga
2
O
3
dielectric heterojunction structures are demonstrated for further improvement of the achievable breakdown field in β-Ga
2
O
3
devices. A record breakdown electric field of 5.7 MV/cm is experimentally measured from the dielectric heterojunction structure. Towards the end of the thesis, future device designs including delta-doped double heterojunction field effect transistors and dielectric heterojunction field effect transistors are introduced.
Committee
Siddharth Rajan (Advisor)
Robert Coffie (Committee Member)
Steven Ringel (Committee Member)
Wu Lu (Committee Member)
Xiaoxue Wang (Committee Member)
Pages
135 p.
Subject Headings
Electrical Engineering
;
Solid State Physics
Keywords
gallium oxide
;
wide bandgap
;
MBE
;
semiconductor device
;
delta dope
;
MESFET
;
field effect transistor
;
high frequency
;
RF device
;
power electronics
;
power device
;
high electric field
;
dielectric heterojunction
;
superjunction
;
high k
;
high permittivity
;
Recommended Citations
Refworks
EndNote
RIS
Mendeley
Citations
Xia, Z. (2020).
Materials and Device Engineering for High Performance β-Ga2O3-based Electronics
[Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587688595358557
APA Style (7th edition)
Xia, Zhanbo.
Materials and Device Engineering for High Performance β-Ga2O3-based Electronics.
2020. Ohio State University, Doctoral dissertation.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=osu1587688595358557.
MLA Style (8th edition)
Xia, Zhanbo. "Materials and Device Engineering for High Performance β-Ga2O3-based Electronics." Doctoral dissertation, Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587688595358557
Chicago Manual of Style (17th edition)
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Document number:
osu1587688595358557
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Copyright Info
© 2020, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.