Article
Chemistry, Physical
Patrick Fiorenza, Corrado Bongiorno, Filippo Giannazzo, Mario S. Alessandrino, Angelo Messina, Mario Saggio, Fabrizio Roccaforte
Summary: This study investigates the impact of SiO2 layers on 4H-SiC, with findings indicating that NO annealing can enhance channel mobility and reduce the total amount of interface states. Electron energy loss spectroscopy reveals that the reduction of traps in the NO annealed sample is attributed to lower amounts of sub-stoichiometric silicon oxide and carbon-related defects at the interface.
APPLIED SURFACE SCIENCE
(2021)
Article
Engineering, Electrical & Electronic
Zhen Wang, Zhaofu Zhang, Chen Shao, John Robertson, Sheng Liu, Yuzheng Guo
Summary: The study systematically investigates the defects at the SiO2/4H-SiC (0001) interface using first-principles calculations, finding that Si-Si antibonding structures are the main cause of gap states. Experimental results suggest that nitrogen passivation is an effective method for fully eliminating the gap states from Si-Si defects, while boron passivation works well for vacancy defects at the suboxide layers. The theoretical findings point towards a combined passivation strategy of nitrogen and boron as an effective approach to enhance the SiO2/4H-SiC interface.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Physics, Applied
Hidetoshi Nakanishi, Tatsuhiko Nishimura, Iwao Kawayama, Masayoshi Tonouchi, Takuji Hosoi, Takayoshi Shimura, Heiji Watanabe
Summary: Terahertz emission spectroscopy (TES) is used to evaluate interface properties between thermally grown oxides and 4H-SiC(0001) substrates. By measuring the emitted THz signal, information on the surface potential change of SiC MOS structures can be obtained, allowing for comparisons between structures with different interface qualities and investigation of the mechanism of THz emission.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Applied
Keita Tachiki, Yusuke Nishiya, Jun-Ichi Iwata, Yu-ichiro Matsushita
Summary: In this study, the effect of introducing nitrogen as a dopant near the SiC/SiO2 interface was investigated using first-principles calculations. It was found that when a highly doped nitrogen layer is introduced within a few nm of the SiC surface, the electronic state is not significantly affected if the doping region is less than 4 nm. However, if the doping region exceeds 4 nm, the quantum confinement effect decreases, resulting in an increase in the electron density induced in the inversion layer. Furthermore, the application of an electric field shifts the peak of the wavefunction away from the interface, reducing electron scattering and improving electron mobility.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Polymer Science
Chenchen Tian, Shuang Wang, Chunmeng Miao, Chao Wang, Lin Xu, Nanying Ning, Ming Tian
Summary: The interfacial structure and chain segment dynamics of nanofiller/polymer composites were studied using quantitative nanomechanical mapping technique. The relationship between the degree of graft of coupling agent on SiO2 and interfacial structure was established, and the formation mechanism of interfacial structure in SiO2/SSBR composites was revealed. The increase in degree of graft led to a thicker interfacial layer, more homogeneous dispersion of SiO2, larger total area of interfacial SSBR layer, lower chain density of SSBR matrix, and a significant decrease in Tg.
Article
Engineering, Electrical & Electronic
Luca Maresca, Ilaria Matacena, Michele Riccio, Andrea Irace, Giovanni Breglio, Santolo Daliento
Summary: This article focuses on the analysis of the effect of SiC/SiO2 interface traps on the C-V curve of a SiC MOSFET through TCAD simulations, as well as proposing guidelines for the calibration of the TCAD model. Qualitative analysis of the impact of SiC/SiO2 interface traps properties on the C-V curve was conducted using TCAD simulations to support the interpretation of experimental C-V curves, and a new approach for simulating the C-V curves of a SiC MOSFET was introduced.
IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS
(2021)
Article
Physics, Applied
Zhen Wang, Zhaofu Zhang, Sheng Liu, Chen Shao, John Robertson, Yuzheng Guo
Summary: In this article, five types of carbon-carbon defects introduced to the SiO2/4H-SiC (0001) interface are systematically investigated through first-principle calculations. The thermal oxidation process of 4H-SiC is analyzed, and it is found that oxygen-poor condition effectively suppresses the formation of carbon-carbon defects. The electronic structure and distribution of electron states for the carbon-carbon defects are obtained, revealing that they cause gap states near the conduction band minimum and act as acceptors.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Mitsuhiro Saito, Hongping Li, Kazutoshi Inoue, Hirofumi Matsuhata, Yuichi Ikuhara
Summary: Optimizing wet oxidation conditions is crucial for obtaining excellent electronic properties in 4H-SiC MOSFET devices, with differences in oxidation rates between Si-face and C-face due to interface structure variations. The formation of an oxidation front by oxygen atom ordering ultimately suppresses interface defects or residual carbon, providing important insights for designing high-performance 4H-SiC MOSFET devices.
Article
Chemistry, Physical
Naxin Zhu, Kaichuang Ma, Xiangyi Xue, Jie Su
Summary: Employing first-principles calculations, the formation and role of the oxidation layer during the high temperature growth process of 4H-SiC substrate were investigated. The oxidation layer disappeared at the 4H-SiC/8-Ga2O3 interface, while abundant electrons were accumulated at the SiO2/β-Ga2O3 contact region.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Lihong Han, Yuanyuan Zou, Baonan Jia, Xiaoning Guan, Huiyan Zhao, Yingshi Hu, Xinhui Zhang, Pengfei Lu
Summary: The atomic and electronic properties of different SiC/SiO2 interfaces were investigated using the first principles method. The terminal types on the SiO2 side and crystal faces of 4H-SiC influenced the interface structures and band alignment. The O-terminated interface structures showed higher conduction band offsets and interface separation work, making them more favorable for SiC-based devices.
SURFACES AND INTERFACES
(2022)
Article
Engineering, Electrical & Electronic
Lijuan Wu, Jiahui Liang, Mengyuan Zhang, Mengjiao Liu, Tengfei Zhang, Gang Yang, Xuanting Song
Summary: This paper analyzes the influence of the channel region and JFET region on the C-V curve of SiC MOSFETs and proposes a method to extract the SiC/SiO2 interface characteristics by fitting the measured C-V curve with the TCAD simulated curve. The extracted interface characteristics are validated by comparing the measured and simulated I-V curves and threshold voltages (VTH) at different lattice temperatures. The extracted interface characteristics and fixed interface charge are then added to the TCAD model for short-circuit simulations, which show that the former fails earlier and has a lower peak short-circuit current due to the different leakage degrees of the hole current and the difference in channel mobility. Finally, P-type blocks are added below the JFET area to reduce the current during a short-circuit transient, improving the capacity to withstand a short circuit by approximately 22.4%.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2023)
Article
Physics, Applied
Junzhe Kang, Kai Xu, Hanwool Lee, Souvik Bhattacharya, Zijing Zhao, Zhiyu Wang, R. Mohan Sankaran, Wenjuan Zhu
Summary: In this study, SiC MISFETs with a triple layer dielectric stack and a ring structure were demonstrated to have a high potential in extreme-temperature electronics. These MISFETs operated up to 50 degrees C with a high on/off current ratio and a low off-state current at elevated temperatures. The gate dielectric stack showed good thermal stability and excellent dielectric interface. The electron mobility also increased with temperature, indicating the suitability of these MISFETs for extreme environments.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
J. Sito, P. Mazur, A. Sabik, A. Trembulowicz, R. Kudrawiec, A. Ciszewski, M. Grodzicki
Summary: This paper investigates the physicochemical properties of organic layers of Alq3, Gaq3, or Erq3 vapor deposited on graphene/6H-SiC(0 0 0 1) surfaces. In situ thermal annealing was used to produce a one monolayer thick graphene termination of the substrate. The formation and characterization of the interfaces were performed under ultrahigh vacuum conditions. XPS/UPS were employed for characterization. XPS results show no chemical reaction between the organic layers and the graphene/6H-SiC(0 0 0 1) surfaces at room temperature. UPS measurements reveal a decrease in the vacuum level due to the adsorption of organic layers, resulting in the initiation of surface dipoles. The HOMO positions and band energy diagrams for the three interfaces were also determined.
APPLIED SURFACE SCIENCE
(2023)
Article
Engineering, Electrical & Electronic
Menghua Wang, Mingchao Yang, Weihua Liu, Jinwei Qi, Songquan Yang, Chuanyu Han, Li Geng, Yue Hao
Summary: The novel post-oxidation annealing process with supercritical N2O fluid effectively enhances the interface properties of SiO2/4H-SiC systems, showing great potential for improving the performance of SiC power MOSFET devices.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Physics, Applied
Hiroki Fujimoto, Takuma Kobayashi, Takayoshi Shimura, Heiji Watanabe
Summary: This paper presents a method to selectively introduce nitrogen at the SiC-side of the SiO2/SiC interface, resulting in significantly low D(it) values near the conduction band edge of SiC. The interface properties were hardly degraded by excimer ultraviolet light irradiation, indicating better stability compared with a NO-nitrided sample.
APPLIED PHYSICS EXPRESS
(2023)
Article
Chemistry, Multidisciplinary
Yu-Chuan Lin, Chenze Liu, Yiling Yu, Eva Zarkadoula, Mina Yoon, Alexander A. Puretzky, Liangbo Liang, Xiangru Kong, Yiyi Gu, Alex Strasser, Harry M. Meyer, Matthias Lorenz, Matthew F. Chisholm, Ilia N. Ivanov, Christopher M. Rouleau, Gerd Duscher, Kai Xiao, David B. Geohegan
Article
Chemistry, Multidisciplinary
Yiyi Gu, Hui Cai, Jichen Dong, Yiling Yu, Anna N. Hoffman, Chenze Liu, Akinola D. Oyedele, Yu-Chuan Lin, Zhuozhi Ge, Alexander A. Puretzky, Gerd Duscher, Matthew F. Chisholm, Philip D. Rack, Christopher M. Rouleau, Zheng Gai, Xiangmin Meng, Feng Ding, David B. Geohegan, Kai Xiao
ADVANCED MATERIALS
(2020)
Article
Nanoscience & Nanotechnology
Krishna P. Koirala, Venkatanarayana P. Sandireddy, Hernando Garcia, Gerd Duscher, Ramki Kalyanaraman
Article
Materials Science, Multidisciplinary
Alexander A. Puretzky, Yu-Chuan Lin, Chenze Liu, Alex M. Strasser, Yiling Yu, Stela Canulescu, Christopher M. Rouleau, Kai Xiao, Gerd Duscher, David B. Geohegan
Correction
Chemistry, Multidisciplinary
Yiyi Gu, Hui Cai, Jichen Dong, Yiling Yu, Anna N. Hoffman, Chenze Liu, Akinola D. Oyedele, Yu-Chuan Lin, Zhuozhi Ge, Alexander A. Puretzky, Gerd Duscher, Matthew F. Chisholm, Philip D. Rack, Christopher M. Rouleau, Zheng Gai, Xiangmin Meng, Feng Ding, David B. Geohegan, Kai Xiao
ADVANCED MATERIALS
(2020)
Article
Chemistry, Multidisciplinary
Gyula Eres, Shinbuhm Lee, John Nichols, Changhee Sohn, Jong Mok Ok, Alessandro R. Mazza, Chenze Liu, Gerd Duscher, Ho Nyung Lee, Daniel E. McNally, Xingye Lu, Milan Radovic, Thorsten Schmitt
ADVANCED FUNCTIONAL MATERIALS
(2020)
Article
Physics, Applied
Krishna Prasad Koirala, Aniruddha Deb, Sara Bey, Tatiana Allen, Ritesh Sachan, Venkatanarayana Prasad Sandireddy, Chenze Liu, Gerd Duscher, James Penner-Hahn, Ramki Kalyanaraman
Summary: Recent studies have found that amorphous oxide thin films made from Fe and lanthanides exhibit rich properties including magnetic, optical, and electronic features, as well as room-temperature magneto-electric coupling with multiferroics. These films show high disorder and slight oxidation after annealing, with high electrical conductivity, Hall mobility, and complex magnetic and optical properties at room temperature.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Ting Zheng, Yu-Chuan Lin, Yiling Yu, Pavel Valencia-Acuna, Alexander A. Puretzky, Riccardo Torsi, Chenze Liu, Ilia N. Ivanov, Gerd Duscher, David B. Geohegan, Zhenhua Ni, Kai Xiao, Hui Zhao
Summary: This study reports the excitonic dynamics of Janus transition metal dichalcogenide monolayers, showing that excitons in Janus structures form faster and have significantly longer radiative recombination lifetime compared to pristine samples. These results provide fundamental insight into the optical properties of Janus transition metal dichalcogenides.
Article
Chemistry, Physical
Krishna Prasad Koirala, Jingxuan Ge, Ramki Kalyanaraman, Gerd Duscher
Summary: This study presents the first evidence of localized interface plasmons in CoAg bimetallic nanoparticles using scanning transmission electron microscopy-electron energy-loss spectroscopy. The oscillation frequency of localized interface plasmons falls between in-plane dipole localized surface plasmon resonance (LSPR) mode and quasiplanar mode, showing stronger resonance compared to in-plane dipole LSPR. The direct detection of plasmons confined to the interface region could drive future engineering for improved plasmonic activity in bimetallic interfaces.
Article
Chemistry, Multidisciplinary
Yiling Yu, Gang Seob Jung, Chenze Liu, Yu-Chuan Lin, Christopher M. Rouleau, Mina Yoon, Gyula Eres, Gerd Duscher, Kai Xiao, Stephan Irle, Alexander A. Puretzky, David B. Geohegan
Summary: The study investigates the synthesis of twisted 2D bilayers through chemical vapor deposition, revealing the preservation of misorientation angles in twisted bilayers and a threshold for their appearance. Simulations and experimental results explain the strain and growth processes during crystal coalescence, shedding light on the formation of grain boundaries and faceting along the GB.
Article
Chemistry, Multidisciplinary
Chenze Liu, Yu-Chuan Lin, Mina Yoon, Yiling Yu, Alexander A. Puretzky, Christopher M. Rouleau, Matthew F. Chisholm, Kai Xiao, Gyula Eres, Gerd Duscher, David B. Geohegan
Summary: This study used in situ laser-heating within a transmission electron microscope to investigate the crystallization and coalescence stages of amorphous precursors deposited by pulsed laser deposition guided by 2D crystalline substrates into van der Waals epitaxial heterostructures.
Article
Materials Science, Multidisciplinary
M. F. Chisholm, D. Shin, G. Duscher, M. P. Oxley, L. F. Allard, J. D. Poplawsky, A. Shyam
Summary: This study accurately determines the atomic structure of semi-coherent precipitate interfaces using aberration-corrected scanning transmission electron microscopy and first-principles calculations, revealing critical features that determine the thermal stability of precipitation-hardened alloys.Unexpected misfit dislocations are found to be key in accommodating the misfit between the matrix and strengthening phase.
Article
Nanoscience & Nanotechnology
Krishna Prasad Koirala, Hernando Garcia, Venkatanarayana Prasad Sandireddy, Ramki Kalyanaraman, Gerd Duscher
Summary: The discovery of giant negative nonlinear refraction and nonlinear Faraday rotation at 1550 nm using Fe-Ag bimetallic nanopyramids was reported, showing a very large third-order nonlinear refractive index and magneto-optical susceptibility. This nanoscale system opens up possibilities for future miniaturization of multifunctional devices at telecommunication wavelengths.
ACS APPLIED NANO MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Kai Wang, Lizhi Zhang, Giang D. Nguyen, Xiahan Sang, Chenze Liu, Yiling Yu, Wonhee Ko, Raymond R. Unocic, Alexander A. Puretzky, Christopher M. Rouleau, David B. Geohegan, Lei Fu, Gerd Duscher, An-Ping Li, Mina Yoon, Kai Xiao
Summary: Defects are common in 2D materials and can greatly influence their properties. The authors have developed a method using Au-assisted chemical vapor deposition to selectively form antisite defects in WS2 monolayers. Experimental and theoretical analyses confirm the effectiveness of this bottom-up synthesis approach, with potential applications in the synthesis of other 2D materials.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Yiyi Gu, Lizhi Zhang, Hui Cai, Liangbo Liang, Chenze Liu, Anna Hoffman, Yiling Yu, Austin Houston, Alexander A. Puretzky, Gerd Duscher, Philip D. Rack, Christopher M. Rouleau, Xiangmin Meng, Mina Yoon, David B. Geohegan, Kai Xiao
Summary: This study reports an ambient-pressure chemical vapor deposition approach to synthesize metastable monoclinic PdSe2. Monoclinic PdSe2 is selectively synthesized under S-deficient conditions, and its structure and properties are characterized by first-principles calculations and experimental techniques. Monoclinic PdSe2 exhibits strong optical anisotropy and high electron mobility, which is of significant importance for the synthesis of other 2D transition metal dichalcogenides.
