scholarly journals Stable Field Emission from Vertically Oriented SiC Nanoarrays

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3025
Author(s):  
Jianfeng Xiao ◽  
Jiuzhou Zhao ◽  
Guanjiang Liu ◽  
Mattew Thomas Cole ◽  
Shenghan Zhou ◽  
...  
Keyword(s):  
Field Enhancement ◽  
Breakdown Field ◽  
Length Variation ◽  
High Electron ◽  
Field Emitter ◽  
Vacuum Electronics ◽  
Aspect Ratios ◽  
Emission Stability ◽  
Chemical Inertness ◽  
Current Emission

Silicon carbide (SiC) nanostructure is a type of promising field emitter due to high breakdown field strength, high thermal conductivity, low electron affinity, and high electron mobility. However, the fabrication of the SiC nanotips array is difficult due to its chemical inertness. Here we report a simple, industry-familiar reactive ion etching to fabricate well-aligned, vertically orientated SiC nanoarrays on 4H-SiC wafers. The as-synthesized nanoarrays had tapered base angles >60°, and were vertically oriented with a high packing density >107 mm−2 and high-aspect ratios of approximately 35. As a result of its high geometry uniformity—5% length variation and 10% diameter variation, the field emitter array showed typical turn-on fields of 4.3 V μm−1 and a high field-enhancement factor of ~1260. The 8 h current emission stability displayed a mean current fluctuation of 1.9 ± 1%, revealing excellent current emission stability. The as-synthesized emitters demonstrate competitive emission performance that highlights their potential in a variety of vacuum electronics applications. This study provides a new route to realizing scalable field electron emitter production.

Removing the Barriers to Next Generation'S Dielectric Films: In Situ Void-Free Planarized Films

1990 ◽  
Vol 203 ◽  
Author(s):  
J.R. Monkowski ◽  
M.A. Logan ◽  
L.F. Wright
Keyword(s):  
Aspect Ratio ◽  
Ion Chromatography ◽  
Field Measurements ◽  
Dielectric Films ◽  
Breakdown Field ◽  
Scanning Electron Micrographs ◽  
Aspect Ratios ◽  
New Process ◽  
Scanning Electron

ABSTRACTIn the next generation of semiconductor devices, minimum dimensions will be smaller, aspect ratios (height to width) of devices features will be larger, and BPSG dielectrics will be challenged to deal with these changes. A new process, which integrates deposition, flow, and anneal of BPSG films, and allows void-free filling of high-aspect-ratio trenches with excellent surface planarization, is presented in this paper. Scanning electron micrographs are used to show the extent of film coverage and planarization. Additional characterization includes ion chromatography, ellipsometry, stress measurements, and breakdown field measurements.

Estimation of the tip field enhancement on a field emitter under laser illumination

2005 ◽  
Vol 86 (9) ◽  
pp. 094101 ◽  
Author(s):  
B. Gault ◽  
F. Vurpillot ◽  
A. Bostel ◽  
A. Menand ◽  
B. Deconihout
Keyword(s):  
Field Enhancement ◽  
Field Emitter ◽  
Laser Illumination

scholarly journals Development of Catalytic-CVD SiNx Passivation Process for AlGaN/GaN-on-Si HEMTs

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 842 ◽  
Author(s):  
Myoung-Jin Kang ◽  
Hyun-Seop Kim ◽  
Ho-Young Cha ◽  
Kwang-Seok Seo
Keyword(s):  
Chemical Vapor ◽  
Drain Current ◽  
High Electron Mobility Transistors ◽  
Breakdown Field ◽  
High Electron ◽  
Electron Mobility Transistors ◽  
Current Collapse ◽  
Passivation Process ◽  
Gan On Si ◽  
Sinx Film

We optimized a silicon nitride (SiNx) passivation process using a catalytic-chemical vapor deposition (Cat-CVD) system to suppress the current collapse phenomenon of AlGaN/GaN-on-Si high electron mobility transistors (HEMTs). The optimized Cat-CVD SiNx film exhibited a high film density of 2.7 g/cm3 with a low wet etch rate (buffered oxide etchant (BOE) 10:1) of 2 nm/min and a breakdown field of 8.2 MV/cm. The AlGaN/GaN-on-Si HEMT fabricated by the optimized Cat-CVD SiNx passivation process, which had a gate length of 1.5 μm and a source-to-drain distance of 6 μm, exhibited the maximum drain current density of 670 mA/mm and the maximum transconductance of 162 mS/mm with negligible hysteresis. We found that the optimized SiNx film had positive charges, which were responsible for suppressing the current collapse phenomenon.

scholarly journals Lightning-Rod Effect of Plasmonic Field Enhancement on Hydrogen-Absorbing Transition Metals

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1235 ◽  
Author(s):  
Norihiko Fukuoka ◽  
Katsuaki Tanabe
Keyword(s):  
Transition Metals ◽  
Metal Surfaces ◽  
Noble Metals ◽  
Field Enhancement ◽  
Operating Conditions ◽  
Optical Systems ◽  
Field Energy ◽  
Enhancement Effect ◽  
Morphological Aspect ◽  
Aspect Ratios

The plasmonic enhancement of electromagnetic field energy density at the sharp tips of nanoparticles or nanoscale surface roughnesses of hydrogen-absorbing transition metals, Pd, Ti, and Ni, is quantitatively investigated. A large degree of energy focusing is observed for these transition metals in the microwave region, even surpassing the enhancement for noble metals according to the conditions. Pd, for instance, exhibits peak field enhancement factors of 6000 and 2 × 108 in air for morphological aspect ratios of 10 and 100, respectively. Metal surfaces possibly contain such degrees of nano- or micro-scale native random roughnesses, and, therefore, the field enhancement effect may have been unknowingly produced in existing electrical and optical systems. In addition, for future devices under development, particularly in hydrogen-related applications, it is desirable to design and optimize the systems, including the choice of materials, structures, and operating conditions, by accounting for the plasmonic local energy enhancement effect around the metal surfaces.

A New Carbon Nanotube-Based Field Enhanced Thermionic Cathode

2004 ◽  
Vol 858 ◽  
Author(s):  
Feng Jin ◽  
Christopher Day
Keyword(s):  
Electron Emission ◽  
Field Enhancement ◽  
Oxide Coating ◽  
Enhancement Effect ◽  
High Electron ◽  
Thermionic Cathode ◽  
Emission Properties ◽  
Effective Work ◽  
Effective Work Function ◽  
Thermionic Cathodes

ABSTRACTThe electron emission properties and field enhancement effects of carbon nanotubes (CNTs) have been extensively studied. However, all of these studies focus only on the field emission aspect of the materials and its application in cold cathode electron emitters. So far, we have not seen any studies in the literature that link CNTs with thermionic cathodes, which are an equally important cathode type because of their many applications. We present a study of field enhanced electron emissions from a new type of cathode: the CNT-based field enhanced thermionic cathode. This new cathode consists of a metal substrate with CNTs grown on top of its surface. The CNTs are coated with thermionic emission materials (BaO, SrO, and CaO). This unique cathode structure takes advantage of both the field enhancement effect from CNTs and the high electron emission capability of thermionic materials. The electron emission properties of this new cathode, particularly the field enhancement factor and effective work function, are compared with the conventional thermionic cathodes that are made of same oxide coating.

Breakdown field enhancement of Si-based MOS capacitor by post-deposition annealing of the reactive sputtered ZrOxNy gate oxide

2016 ◽  
Vol 122 (2) ◽  
Author(s):  
Chun Chet Chew ◽  
Kian Heng Goh ◽  
Mohammad Saleh Gorji ◽  
Chee Ghuan Tan ◽  
S. Ramesh ◽  
...  
Keyword(s):  
Field Enhancement ◽  
Gate Oxide ◽  
Breakdown Field ◽  
Post Deposition Annealing ◽  
Mos Capacitor ◽  
Post Deposition

scholarly journals High Lateral Breakdown Voltage in Thin Channel AlGaN/GaN High Electron Mobility Transistors on AlN/Sapphire Templates

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 690 ◽  
Author(s):  
Idriss Abid ◽  
Riad Kabouche ◽  
Catherine Bougerol ◽  
Julien Pernot ◽  
Cedric Masante ◽  
...  
Keyword(s):  
Breakdown Voltage ◽  
Electron Mobility ◽  
High Electron Mobility Transistors ◽  
Channel Structure ◽  
Breakdown Field ◽  
High Electron ◽  
High Electron Mobility ◽  
Electron Mobility Transistors ◽  
Thin Channel ◽  
Channel Configuration

In this paper, we present the fabrication and Direct Current/high voltage characterizations of AlN-based thin and thick channel AlGaN/GaN heterostructures that are regrown by molecular beam epitaxy on AlN/sapphire. A very high lateral breakdown voltage above 10 kV was observed on the thin channel structure for large contact distances. Also, the buffer assessment revealed a remarkable breakdown field of 5 MV/cm for short contact distances, which is far beyond the theoretical limit of the GaN-based material system. The potential interest of the thin channel configuration in AlN-based high electron mobility transistors is confirmed by the much lower breakdown field that is obtained on the thick channel structure. Furthermore, fabricated transistors are fully functional on both structures with low leakage current, low on-resistance, and reduced temperature dependence as measured up to 300 °C. This is attributed to the ultra-wide bandgap AlN buffer, which is extremely promising for high power, high temperature future applications.

Study of Effective Graded Oxide Capacitance and Length Variation on Analog, RF and Power Performances of Dual Gate Underlap MOS-HEMT

2021 ◽  
Author(s):  
Sneha Ghosh ◽  
Anindita Mondal ◽  
Mousiki Kar ◽  
Atanu Kundu
Keyword(s):  
Dielectric Material ◽  
Drain Current ◽  
High Electron Mobility Transistor ◽  
Oxide Semiconductor ◽  
Superior Performance ◽  
Length Variation ◽  
High Electron ◽  
Power Performance ◽  
Output Resistance ◽  
Transistor Mos

Abstract Comparative analysis of a Symmetric Heterojunction Underlap Double Gate (U-DG) GaN/AlGaN Metal Oxide Semiconductor High Electron Mobility Transistor (MOS-HEMT) on varying the effective capacitance by using different oxide materials on source and drain sides, and determination of optimum length of oxides for the superior device performance has been presented in this work. This paper shows a detailed performance analysis of the Analog Figure of Merits (FoMs) like variation of Drain Current (IDS), Transconductance (gm), Output Resistance (R0), Intrinsic Gain (gmR0), RF FoMs like cut-off frequency (fT), maximum frequency of oscillation (fMAX), gate to source resistance (RGS), gate to drain resistance (RGD), gate to drain capacitance(CGD), gate to source capacitance (CGS) and total gate capacitance (CGG) using Non-Quasi-Static (NQS) approach. Power analysis includes Output power (Pout), Gain in dBm and power output efficiency (POE) have been studied. Studies reveal that the device with higher dielectric material towards source side shows superior performance. On subsequently changing the proportion of two oxides in a layer by varying length, it is observed that as the proportion of oxide increases the device demonstrates more desirable Analog and RF characteristics while best power performance is obtained from device with equal lengths of HfO2 and SiO2.

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