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13 pages, 2164 KiB

Open AccessArticle

Breakdown Characteristics of Ga₂O₃-on-SiC Metal-Oxide-Semiconductor Field-Effect Transistors

by Maolin Zhang, Lei Wang, Kemeng Yang, Jiafei Yao, Weihua Tang and Yufeng Guo

Crystals 2023, 13(6), 917; https://doi.org/10.3390/cryst13060917 - 06 Jun 2023

Cited by 1 | Viewed by 1293

Abstract

Ultra-wide bandgap semiconductor gallium oxide (Ga₂O₃) features a breakdown strength of 8 MV/cm and bulk mobility of up to 300 cm²V⁻¹s⁻¹, which is considered a promising candidate for next-generation power devices. However, its [...] Read more.

Ultra-wide bandgap semiconductor gallium oxide (Ga₂O₃) features a breakdown strength of 8 MV/cm and bulk mobility of up to 300 cm²V⁻¹s⁻¹, which is considered a promising candidate for next-generation power devices. However, its low thermal conductivity is reckoned to be a severe issue in the thermal management of high-power devices. The epitaxial integration of gallium oxide thin films on silicon carbide (SiC) substrates is a possible solution for tackling the cooling problems, yet premature breakdown at the Ga₂O₃/SiC interface would be introduced due to the relatively low breakdown strength of SiC (3.2 MV/cm). In this paper, the on-state properties as well as the breakdown characteristics of the Ga₂O₃-on-SiC metal-oxide-semiconductor field-effect transistor (MOSFET) were investigated by using the technology computer-aided design (TCAD) approach. Compared with the full-Ga₂O₃ MOSFET, the lattice temperature of the Ga₂O₃-on-SiC MOSFET was decreased by nearly 100 °C thanks to the high thermal conductivity of SiC. However, a breakdown voltage degradation of >40% was found in an unoptimized Ga₂O₃-on-SiC MOSFET. Furthermore, by optimizing the device structure, the breakdown voltage degradation of the Ga₂O₃-on-SiC MOSFET is significantly relieved. As a result, this work demonstrates the existence of premature breakdown in the Ga₂O₃-on-SiC MOSFET and provides feasible approaches to further enhance the performance of hetero-integrated Ga₂O₃ power devices. Full article

(This article belongs to the Special Issue Wide Bandgap Semiconductor Electronics and Optoelectronics)

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10 pages, 3676 KiB

Open AccessArticle

One-Step Preparation of Si-Doped Ultra-Long β-Ga₂O₃ Nanowires by Low-Pressure Chemical Vapor Deposition

by Minglei Tang, Guodong Wang, Songhao Wu and Yang Xiang

Crystals 2023, 13(6), 898; https://doi.org/10.3390/cryst13060898 - 31 May 2023

Cited by 1 | Viewed by 1050

Abstract

In this work, we prepared ultra-long Si-doped β-Ga₂O₃ nanowires on annealed Al₂O₃-film/Si substrate by low-pressure chemical vapor deposition (LPCVD) assisted by Au as catalyst. The length of nanowires exceeds 300 μm and diameters range from [...] Read more.

In this work, we prepared ultra-long Si-doped β-Ga₂O₃ nanowires on annealed Al₂O₃-film/Si substrate by low-pressure chemical vapor deposition (LPCVD) assisted by Au as catalyst. The length of nanowires exceeds 300 μm and diameters range from ~30 to ~100 nm in one-dimensional structures. The nanowires show good crystal quality and exhibit (201) orientation, confirmed by transmission electron microscopy and X-ray diffraction analysis. The PL spectrum obtained from these β-Ga₂O₃ nanowires has three obvious blue luminescence peaks at 398 nm (3.12 eV), 440 nm (2.82 eV), and 492 nm (2.51 eV). The electrical properties obtained from Si-doped β-Ga₂O₃ nanowires exhibit good conductivity. A metal-semiconductor-metal device is made by using Ti/Au as the electrode, and the device current reaches 200 pA at a bias voltage of 3 V. Our results show that ultra-long Si-doped β-Ga₂O₃ nanowires can be grown directly on the surface of Al₂O₃-film/Si substrates. These nanowires have a very high length-diameter ratio and good electrical properties. A possible mechanism for Si doping is also presented. Full article

(This article belongs to the Special Issue Wide Bandgap Semiconductor Electronics and Optoelectronics)

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12 pages, 2918 KiB

Open AccessArticle

Investigation on β-Ga₂O₃-Based Schottky Barrier Diode with Floating Metal Rings

by Suhao Yao, Kemeng Yang, Lili Yang, Ganrong Feng, Maolin Zhang, Yufeng Guo and Weihua Tang

Crystals 2023, 13(4), 666; https://doi.org/10.3390/cryst13040666 - 12 Apr 2023

Viewed by 1560

Abstract

In this study, the performance of Schottky barrier diodes (SBD) based on β-Ga₂O₃ with floating metal rings (FMR) was investigated using numerical simulations with Technology Computer-Aided Design (TCAD) software. The simulation parameters of β-Ga₂O₃, [...] Read more.

In this study, the performance of Schottky barrier diodes (SBD) based on β-Ga₂O₃ with floating metal rings (FMR) was investigated using numerical simulations with Technology Computer-Aided Design (TCAD) software. The simulation parameters of β-Ga₂O₃, including those in barrier lowering, impact ionization, and image-force-lowering models, were extracted from experimental results. Similar forward conduction characteristics to SBDs without FMRs were exhibited by the device, and its breakdown characteristics were influenced by structural parameters such as FMR spacing, width, number, epitaxial layer thickness, and doping concentration. A breakdown voltage of 2072 V was achieved by the optimized device at a doping concentration of 10¹⁶ cm⁻³, which was 2.5 times higher than that of a device without FMRs. This study also indicated that for general doping concentrations and epitaxial layer thicknesses, the breakdown voltage with such structures can reach at least 1.5 times higher than that of a device without FMRs. Overall, insights into optimizing the design of β-Ga₂O₃-based SBDs with FMRs were provided in this study. Full article

(This article belongs to the Special Issue Wide Bandgap Semiconductor Electronics and Optoelectronics)

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13 pages, 5237 KiB

Open AccessArticle

Insight into the Structural, Mechanical and Optoelectronic Properties of Ternary Cubic Barium-Based BaMCl₃ (M = Ag, Cu) Chloroperovskites Compounds

by Mudasser Husain, Abd Ullah, Ali Algahtani, Vineet Tirth, Tawfiq Al-Mughanam, Abdulaziz H. Alghtani, Nourreddine Sfina, Khaoula Briki, Hind Albalawi, Mohammed A. Amin, Ahmed Azzouz-Rached and Nasir Rahman

Crystals 2023, 13(1), 140; https://doi.org/10.3390/cryst13010140 - 13 Jan 2023

Cited by 9 | Viewed by 1638

Abstract

Prediction of new materials is crucial for the advancement of technology. Here, in this research work, the first-principle computation has been conducted utilizing the WIEN2K package to probe the structural, electronic, mechanical, and optical properties of barium-based chloroperovskites BaMCl₃ (M = Ag, [...] Read more.

Prediction of new materials is crucial for the advancement of technology. Here, in this research work, the first-principle computation has been conducted utilizing the WIEN2K package to probe the structural, electronic, mechanical, and optical properties of barium-based chloroperovskites BaMCl₃ (M = Ag, Cu) compounds. The optimized lattice constants are calculated for both compounds which are 9.90 Bohr for BaAgCl₃ and 9.38 Bohr for BaCuCl₃. To obtain better and more precise results for the electronic band’s structure, TDOS and PDOS (total and partial density of states), and the TB-mBJ potential approximation are employed. The indirect band gap (R–Γ) is found for both compounds having values of 1.173 eV and 2.30 eV for BaCuCl₃ and BaAgCl₃, respectively, which depicts its semiconducting nature. The calculation of elastic properties is conducted with IRelast code. The Cauchy pressure, Bulk modulus, Young’s modulus, Shear modulus, anisotropic ratio, Kleinman parameters, and Poisson’s ratio are calculated from the obtained elastic constants. The computation of elastic parameters indicates that the interested chloroperovskites are anisotropic, mechanically stable, hard to scratch, and ductile. From 0 eV to 40 eV incident photon energy ranges, the various optical parameter such as refractive index, absorption coefficient, dielectric function, reflectivity, extinction coefficient, and optical conductivity are analyzed. These compounds absorb maximum light within 5 to 25 eV incident photon energy. Hence, these materials are good light absorbers, therefore, they can be used in optoelectronic devices for high-frequency applications. Full article

(This article belongs to the Special Issue Wide Bandgap Semiconductor Electronics and Optoelectronics)

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9 pages, 4123 KiB

Open AccessArticle

Investigation on the Negative Capacitance Field Effect Transistor with Dual Ferroelectric Region

by Jia-Fei Yao, Xue Han, Xin-Peng Zhang, Jin-Cheng Liu, Ming-Yuan Gu, Mao-Lin Zhang, Ke-Han Yu and Yu-Feng Guo

Crystals 2022, 12(11), 1545; https://doi.org/10.3390/cryst12111545 - 29 Oct 2022

Cited by 2 | Viewed by 1771

Abstract

This paper proposes a new structure of the negative capacitance field effect transistor (NCFET), which features of the dual ferroelectric region (DFR) when compared to the conventional NCFET. The dual ferroelectric region with FE1 region and FE2 region forms a non-uniform voltage amplification [...] Read more.

This paper proposes a new structure of the negative capacitance field effect transistor (NCFET), which features of the dual ferroelectric region (DFR) when compared to the conventional NCFET. The dual ferroelectric region with FE1 region and FE2 region forms a non-uniform voltage amplification effect, leads to the significantly improvement of the gate control ability and modulates the electric characteristics of the NCFET. The mechanism of the voltage amplification effect, polarization reversal, channel surface electric field, and ferroelectric polarization intensity distributions are investigated. The influences of the ferroelectric parameters α and β on the electric characteristics are discussed. The results show that the DFR-NCFET is able to obtain a subthreshold swing (SS) below the Boltzmann limit (60 mV/dec) by increasing the ferroelectric parameter α of the FE2 region. Full article

(This article belongs to the Special Issue Wide Bandgap Semiconductor Electronics and Optoelectronics)

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12 pages, 11844 KiB

Open AccessArticle

Investigation of Electronic and Optical Properties of (Cs, Br, Cs-Br) Doped Mono-Layer Hexagonal Boron Nitride Using First Principles

by Yangchen Fu, Wenchao Zhang, Zhihua Fan, Hongcheng Jiang, Yuhang Hou, Qiuyu Luo and Yi Wang

Crystals 2022, 12(10), 1406; https://doi.org/10.3390/cryst12101406 - 05 Oct 2022

Viewed by 1927

Abstract

Research on the effect of alternative doping on the photoelectric properties of boron nitride is still at an early stage. In particular, research on hexagonal boron nitride’s diatomic co-doping is still rarely studied. In this work, first-principles calculations are selected as the main [...] Read more.

Research on the effect of alternative doping on the photoelectric properties of boron nitride is still at an early stage. In particular, research on hexagonal boron nitride’s diatomic co-doping is still rarely studied. In this work, first-principles calculations are selected as the main method to investigate the electronic structure and optical properties of different atoms used to dope hexagonal boron nitride (h-BN). The band gap value of intrinsic h-BN is 4.66 eV. The band gap was changed after Cs, Br, and Cs-Br doping. The results show that the band gap is 4.61 eV when the Br atom replaces the N atom, while the band gap of h-BN doped with Cs is 3.52 eV. Additionally, the band gap width can be reduced to a typical narrower band gap width of 3.19 eV when Cs-Br is used for doping. At the same time, the complex dielectric function representing the optical properties is calculated after Cs, Br, and Cs-Br doping. The optical absorption peaks of Cs-Br-doped h-BN are weaker at low-frequency conditions. The optical absorption of h-BN can be modified by Cs doping, Br doping, and Cs-Br co-doping in the near-infrared, visible, or portion of the near-ultraviolet bands, which makes the doped material more suited for photoelectric detectors in the relevant frequency bands. Full article

(This article belongs to the Special Issue Wide Bandgap Semiconductor Electronics and Optoelectronics)

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11 pages, 3211 KiB

Open AccessArticle

A Deep-Ultraviolet Photodetector of a Hybrid Organic-Inorganic p-CoPc/n-Ga₂O₃ Heterostructure Highlighting Ultra-Sensitive

by Xiaohui Qi, Xueqiang Ji, Jianying Yue, Song Qi, Jinjin Wang, Peigang Li and Weihua Tang

Crystals 2022, 12(9), 1284; https://doi.org/10.3390/cryst12091284 - 11 Sep 2022

Cited by 6 | Viewed by 1654

Abstract

A practical method for organic–inorganic hybrid heterojunction photodetector by spin-coating the cobalt phthalocyanine (CoPc) solution onto the β-gallium oxide (β-Ga₂O₃) film is available to realize the sensitive detection of ultraviolet light signals. We have carefully measured and calculated the [...] Read more.

A practical method for organic–inorganic hybrid heterojunction photodetector by spin-coating the cobalt phthalocyanine (CoPc) solution onto the β-gallium oxide (β-Ga₂O₃) film is available to realize the sensitive detection of ultraviolet light signals. We have carefully measured and calculated the optoelectronic performance of the prepared device. The device demonstrates excellent rectification characteristics under different light intensities, and the rectification ratio reaches 144.96 under 900 μW/cm² at ±5 V. Benefiting from the construction of CoPc/Ga₂O₃ heterojunction, the device shows an extremely low dark current of 5.73 fA, a high detectivity of 1.92 × 10¹⁷ Jones, a responsivity of 18.4 mA/W, and a high light-to-dark current ratio of 3.76 × 10⁶. In addition, the intrinsic physical mechanism of the device is investigated through the energy band diagram under different conditions. The device is equipped with the possibility to work under self-powered mode and has good stability in the air environment. Full article

(This article belongs to the Special Issue Wide Bandgap Semiconductor Electronics and Optoelectronics)

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6 pages, 949 KiB

Open AccessArticle

On-State Voltage Drop Analytical Model for 4H-SiC Trench IGBTs

by Yanjuan Liu, Dezhen Jia and Junpeng Fang

Crystals 2022, 12(5), 582; https://doi.org/10.3390/cryst12050582 - 22 Apr 2022

Cited by 1 | Viewed by 1453

Abstract

In this paper, a model for the forward voltage drop in a 4H-SiC trench IGBT is developed. The analytical model is based on the 4H-SiC trench MOSFET voltage model and the hole-carrier concentration profile in the N-drift region for a conventional 4H-SiC trench [...] Read more.

In this paper, a model for the forward voltage drop in a 4H-SiC trench IGBT is developed. The analytical model is based on the 4H-SiC trench MOSFET voltage model and the hole-carrier concentration profile in the N-drift region for a conventional 4H-SiC trench IGBT. Moreover, an on-state voltage drop analytical model is validated using a 2D numerical simulation, and the simulation results demonstrate that there is good agreement between the ATLAS simulation data and analytic solutions. Full article

(This article belongs to the Special Issue Wide Bandgap Semiconductor Electronics and Optoelectronics)

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Review

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28 pages, 3700 KiB

Open AccessReview

β-Ga₂O₃-Based Power Devices: A Concise Review

by Maolin Zhang, Zeng Liu, Lili Yang, Jiafei Yao, Jing Chen, Jun Zhang, Wei Wei, Yufeng Guo and Weihua Tang

Crystals 2022, 12(3), 406; https://doi.org/10.3390/cryst12030406 - 16 Mar 2022

Cited by 37 | Viewed by 5939

Abstract

Ga₂O₃ has gained intensive attention for the continuing myth of the electronics as a new-generation wide bandgap semiconductor, owing to its natural physical and chemical properties. In this review article, we selectively summarized the recent advances on the experimental and [...] Read more.

Ga₂O₃ has gained intensive attention for the continuing myth of the electronics as a new-generation wide bandgap semiconductor, owing to its natural physical and chemical properties. In this review article, we selectively summarized the recent advances on the experimental and theoretical demonstration of β-Ga₂O₃-based power devices, including Schottky barrier diodes and field-effect transistors, aiming for an inherent comprehending of the operating mechanisms, discussion on the obstacles to be addressed, and providing some comprehensive guidance for further developments. In the short run, Ga₂O₃ may well be promising to lead power electronics. Full article

(This article belongs to the Special Issue Wide Bandgap Semiconductor Electronics and Optoelectronics)

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