Ultrawide Bandgap Semiconductors

Front Cover
Ultrawide Bandgap Semiconductors
Copyright
Contents
Contributors
Preface
Chapter One: Fundamental technologies for gallium oxide transistors
1. Introduction
2. Lateral FET
2.1. MESFET
2.2. Depletion-mode FET
2.2.1. Fabrication of ohmic contact using Si-ion implantation doping
2.2.2. Gate dielectric
2.2.3. D-mode MOSFET
2.2.4. Field-plated MOSFET
2.2.5. Surface activated bonding for thermal management
2.2.6. Reduction in leakage current at epilayer/substrate interface
2.2.7. Highly scaled MOSFET for RF applications
2.2.8. Gamma-ray tolerance of MOSFET
2.3. Enhancement-mode FET
3. Vertical FET
3.1. Vertical D-mode FET
3.1.1. Difficulty in realizing p-type Ga2O3
3.1.2. N-ion implantation doping to form deep-acceptor p-Ga2O3
3.1.3. Current-aperture FET
3.2. Vertical E-mode FET
4. Conclusion
References
Chapter Two: Advanced concepts in Ga2O3 power and RF devices
1. Advantage of Ga2O3 for power and RF devices
2. Practical maximum surface electric field
2.1. In Schottky junctions
2.2. In MOS structures
3. Advanced device concept 1: High barrier height Schottky junctions
4. Advanced device concept 2: RESURF via trench structures
4.1. Overview
4.2. Development of Ga2O3 trench Schottky barrier diodes
4.3. Design of the electric-field profile
5. Summary
References
Chapter Three: β-(AlxGa(1-x))2O3 epitaxial growth, doping and transport
1. Thermodynamics of (AlxGa(1-x))2O3
2. Molecular beam epitaxy of β-(Alx,Ga(1-x))2O3
3. Metal organic chemical vapor deposition of (Al,Ga)2O3
4. Doping and transport in (Alx,Ga(1-x))2O3
5. Doping and transport in (Alx,Ga(1-x))2O3/β-Ga2O3 heterostructures
6. Outlook for future work
References
Chapter Four: Thermal science and engineering of β-Ga2O3 materials and devices
1. Crystal structure and thermal conductivity of bulk β-Ga2O3
2. Thermal conductivity of β-Ga2O3 nanostructures
3. Heterogeneous integration with diamond
4. Wafer bonding of monocrystalline β-Ga2O3 on SiC
5. Device-level cooling
References
Chapter Five: Controlling different phases of gallium oxide for solar-blind photodetector application
1. Growth of Ga2O3 polymorphs
1.1. Bulk crystal growth
1.2. Epitaxial growth of Ga2O3
1.2.1. Epitaxial growth of β-Ga2O3
1.2.2. Epitaxial growth of α-Ga2O3
1.2.3. Epitaxial growth of ε-Ga2O3
1.2.4. Epitaxial growth of other phases of Ga2O3
1.3. Doping of Ga2O3
2. Photodetectors based on different Ga2O3 polymorphs
2.1. Photodetectors based on β-Ga2O3
2.1.1. MSM photodetectors based on β-Ga2O3
2.1.2. FET photodetectors based on β-Ga2O3
2.2. Photodetectors based on α-Ga2O3
2.3. Photodetectors based on ε-Ga2O3
2.4. Photodetectors based on other phase Ga2O3
2.5. Photodetectors based on amorphous Ga2O3 (a-Ga2O3)
3. Ga2O3 photodetectors based on composite structure
3.1. Ga2O3 photodetectors decorated by nano/micro particles
3.2. Ga2O3 photodetectors decorated by 2D materials
3.3. Ga2O3-based wide-bandgap heterojunction photodetectors
3.4. Photodetectors based on Ga2O3 with phase junction
4. Summary
Reference
Chapter Six: Nanoscale AlGaN and BN: Molecular beam epitaxy, properties, and device applications
1. Introduction
2. Epitaxy and characterization
2.1. AlGaN nanostructures
2.1.1. Epitaxy and characterization of AlGaN nanocrystals
2.1.2. AlN nanowires
2.2. BN
3. Optical and excitonic properties
3.1. Excitonic emission of AlN
3.2. Excitonic emission of monolayer GaN
3.3. Direct and indirect bandgap of hBN
4. Device applications
4.1. Mid and deep-UV LEDs
4.1.1. Tunnel junction LEDs
4.1.2. Monolayer GaN LEDs
4.1.3. AlN nanowire LEDs
4.2. Electrically pumped UV laser diodes
4.3. Other emerging device applications
5. Conclusion
Acknowledgments
Conflict of interest
References
Chapter Seven: High-Al-content heterostructures and devices
1. Introduction
2. Power switching and RF figures-of-merit
3. High-Al-content AlGaN HEMTs for power switching
4. High-Al-content AlGaN HEMTs for radio-frequency amplifiers
4.1. Mobility
4.2. Saturation velocity
4.3. Sheet carrier density
4.4. Critical electric field
4.5. Bandwidth
4.6. Device results
4.7. Summary
5. Processing and fabrication challenges for high-Al-content AlGaN heterostructures
5.1. Surface oxidation and removal
5.2. Surface fluorine contamination
5.3. Plasma dry etch
6. Summary
Acknowledgments
References
Chapter Eight: AlN nonlinear optics and integrated photonics
1. Introduction
2. Quadratic nonlinearity
2.1. High-efficiency second-harmonic generation
2.1.1. Modeling of SHG efficiencies
2.1.2. Device design, fabrication, and characterization
2.1.3. Optimization of second-harmonic generation
2.1.4. Discussion
2.2. Nanophotonic optical parametric oscillators
2.2.1. Modeling of optical parametric oscillation behavior
2.2.2. Device fabrication and second-harmonic characterization
2.2.3. Optical parametric oscillation and tunability
2.2.4. Discussion
3. Cubic nonlinearity
3.1. Chip-integrated Raman lasers
3.1.1. Spontaneous Raman spectroscopy
3.1.2. Principle and device configurations
3.1.3. Polarization-dependent Raman lasing
3.1.4. Discussion
3.2. Kerr frequency combs
3.2.1. Device engineering
3.2.2. Broadband Kerr frequency combs
3.2.3. Soliton mode-locking
3.2.4. Discussion
4. Simultaneously quadratic and cubic nonlinearities
4.1. Near-visible frequency combs
4.1.1. Principles
4.1.2. Translation of Kerr comb spectra
4.1.3. Discussion
4.2. Ultraviolet supercontinuum combs
4.2.1. Concept and device engineering
4.2.2. Phase-matched UV microcombs
4.2.3. Coherence characterization
4.2.4. Discussion
5. Conclusion and prospects
References
Chapter Nine: Material epitaxy of AlN thin films
1. Introduction
2. Substrate selection for AlN film growth
2.1. AlN grown on sapphire
2.2. AlN on SiC
2.3. AlN on Si
3. Growth techniques
3.1. Molecular beam epitaxy
3.2. Metalorganic vapor phase epitaxy
3.2.1. MOVPE systems and the basic growth principle
3.3. Physical vapor deposition
4. Growth processes for high crystalline quality AlN
4.1. Epitaxial growth of AlN on flat sapphire by MOVPE
4.2. AlN growth: ELOG method
4.3. High temperature annealing of AlN films
5. Conclusion and outlook
References
Chapter Ten: Development of AlN integrated photonic platform for octave-spanning supercontinuum generation in visible spe ...
1. Introduction
2. Material characterizations and device fabrication
2.1. Material characterizations on AlN
2.2. Fabrication of AlN integrated waveguides
3. Numerical modeling on the waveguide performance
3.1. Semi-analytical model for defect induced scattering losses
3.2. Evaluation of scattering loss in visible spectrum
4. Octave-spanning supercontinuum generation from AlN waveguides
4.1. Second harmonic generation and soliton dynamics within AlN waveguides
4.2. Octave-spanning supercontinuum generation
5. Other emerging applications and platforms
6. Conclusion
Acknowledgment
Conflict of interest
References
Chapter Eleven: AlGaN-based thin-film ultraviolet laser diodes and light-emitting diodes
1. Introduction and significance of ultraviolet laser diodes and light-emitting diodes
2. State-of-the-art of ultraviolet laser diodes
2.1. Electrically driven UV laser diodes on sapphire
2.2. Electrically driven UV laser diodes on native GaN substrate
2.3. Electrically driven UV laser diodes on native AlN substrate
2.4. Possible electrically driven UV laser on SiC
2.5. Summary
3. State-of-the-art of DUV LEDs
3.1. The reasons behind low performance of DUV LEDs
3.2. IQE challenge and solutions
3.3. LEE challenge and solutions
3.4. WPE challenge and solutions
3.5. Conclusion and prospects/outlook
References
Chapter Twelve: Electrical transport properties of hexagonal boron nitride epilayers
1. Introduction
2. Prospects of n- and p-type doping of h-BN
2.1. Mg doping
2.2. Si doping
2.3. Carbon doping
3. Criteria of h-BN as thermal neutron detector materials
3.1. Thickness requirement
3.2. Requirements in background carrier concentration and dark electrical resistivity
3.3. Necessary conditions for attaining high charge collection efficiencies
4. Vertical electrical transport properties and parameters
4.1. Carrier mobility-lifetime product and surface recombination field characterization
4.2. Charge collection efficiency characterization
4.3. Thermal neutron detection efficiency characterization
5. Lateral electrical transport properties and parameters
5.1. Lateral charge carrier transport properties probed by time-of-flight technique
5.2. Attainment of 1cmBN lateral neutron detectors with unprecedented efficiency
5.3. Characterizing transport parameters under thermal neutron irradiation
6. Dominant native and point defects in h-BN
6.1. Oxygen impurities
6.2. Probing dominant defects by photoexcitation spectroscopy
7. Concluding remarks
Acknowledgments
References
Index
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