Effect of Sb Addition on the Electrical Characteristics of Bi-Based ZnO Varistors Containing Zr and Y

The effects of adding Sb to a BiMnCoSiCrNiYZr-added ZnO varistor (with the same composition as a commercial varistor) on the varistor voltage, leakage current, and resistance to electrical degradation were investigated. Bi is incorporated in spinel particles, and δ-Bi2O3eventually disappears with the addition of small amounts of Bi, especially as the amount of Sb2O3added increased. Reduction in both the nonlinearity index and the amount of δ-Bi2O3for small amounts of added Bi with the addition of more than approximately 1.25 mol% Sb2O3demonstrates that Sb inhibits Bi2O3from forming deep interfacial impurity levels at the grain boundaries. The sample containing 1.2 mol% Bi2O3, 1.0 mol% ZrO2, 1.0 mol% Y2O3, and 1.5 mol% Sb2O3added exhibits a high varistor voltage (approximately 630 V/mm), high resistance to electrical degradation and low leakage current.

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Effect of Simultaneous Addition of Zr and Y on Electrical Characteristics of ZnO Varistors

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.485.257 ◽

2011 ◽

Vol 485 ◽

pp. 257-260 ◽

Cited By ~ 1

Author(s):

Takayuki Watanabe ◽

Ai Fukumori ◽

Yuji Akiyamna ◽

Yuuki Sato ◽

Shinzo Yoshikado

Keyword(s):

Leakage Current ◽

Nonlinear Coefficient ◽

The Other ◽

Electrical Characteristics ◽

Simultaneous Addition ◽

Zno Varistor ◽

Low Leakage ◽

Electrical Degradation ◽

Low Leakage Current ◽

Zno Varistors

The effect of simultaneously adding Zr and Y to Bi–Mn–Co–Sb–Si–Cr–Ni-added ZnO varistors (having the same composition as a commercial varistor) on the varistor voltage, leakage current, and resistance to electrical degradation were investigated. Varistor voltage increased with increasing amount of Y for addition of 0–2 mol % Zr. On the other hand, the nonlinear coefficient α prior to electrical degradation changed very little on the addition of both Y and Zr. With the addition of approximately 1 mol% Zr, the leakage current decreased with increasing amount of Y added. A ZnO varistor with a varistor voltage of approximately 600 V/m, a low leakage current, and excellent resistance to electrical degradation was fabricated by adding approximately 2 mol% Y and approximately 1 mol% Zr.

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Fabrication of Bismuth-Based Zinc Oxide Varistors with High Varistor Voltage by Addition of Tin and Yttrium Oxides

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.582.198 ◽

2013 ◽

Vol 582 ◽

pp. 198-201

Author(s):

Yosuke Tokoro ◽

Takayuki Watanabe ◽

Yuuki Sato ◽

Shinzo Yoshikado

Keyword(s):

Zinc Oxide ◽

Leakage Current ◽

Yttrium Oxide ◽

Tin Oxide ◽

Molar Ratio ◽

Low Leakage ◽

Electrical Degradation ◽

Low Leakage Current ◽

Zno Varistors ◽

Zinc Oxide Varistors

The effects of the addition of tin oxide (SnO2) and yttrium oxide (Y2O3) to bismuth (Bi)-manganese (Mn)-cobalt (Co)-silicon (Si)-chromium (Cr)-nickel (Ni)-added zinc oxide (ZnO) varistors (a basic varistor) on the varistor voltage, resistance to electrical degradation, and leakage current were investigated. The addition of SnO2increased both the varistor voltage and the resistance to electrical degradation. However, simultaneous addition of both SnO2and Y2O3increased the varistor voltage but the resistance to electrical degradation deteriorated. ZnO varistors with varistor voltage over approximately 520 V/mm, excellent resistance to electrical degradation, and low leakage current could be obtained by adding SnO2with SnO2-to-ZnO molar ratio of approximately 1:10 to the basic varistor.

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Electrical Characteristics of New LDD Poly-Si TFT with MIS-Alignment Tolerant Structure for AMLCDs

MRS Proceedings ◽

10.1557/proc-471-137 ◽

1997 ◽

Vol 471 ◽

Author(s):

Byung-Hyuk Min ◽

Jerzy Kanicki

Keyword(s):

Leakage Current ◽

Experimental Results ◽

Electrical Characteristics ◽

Current Ratio ◽

Low Leakage ◽

Kink Effect ◽

Low Leakage Current ◽

Dual Gate ◽

Output Characteristics

ABSTRACTA new LDD poly-Si TFT structure having symmetrical electrical characteristics independent of the process induced mis-alignment is described in this paper. Based on the experimental results, we have established there is no difference between the forward and reverse characteristics and a low leakage current, comparable to a conventional LDD poly-Si TFT, has been maintained for this new poly-Si TFTs. The maximum ON/OFF current ratio of about 1×108 is obtained for the LDD length of 1.0 μm. In addition, the kink effect in the output characteristics is remarkably improved in the new TFTs in comparison to the conventional non-LDD single- or dual-gate TFTs.

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Tailoring low leakage current and high nonlinear coefficient of a Y-doped ZnO varistor by indium doping

Materials Letters ◽

10.1016/j.matlet.2016.10.100 ◽

2017 ◽

Vol 188 ◽

pp. 77-79 ◽

Cited By ~ 18

Author(s):

Pengfei Meng ◽

Shanglin Lyu ◽

Jun Hu ◽

Jinliang He

Keyword(s):

Leakage Current ◽

Nonlinear Coefficient ◽

Zno Varistor ◽

Low Leakage ◽

Indium Doping ◽

Low Leakage Current ◽

Doped Zno

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Reverse Electrical Characteristics of 4H-SiC JBS Diodes Fabricated on In-House Substrate with Low Threading Dislocation Density

Materials Science Forum ◽

10.4028/www.scientific.net/msf.679-680.694 ◽

2011 ◽

Vol 679-680 ◽

pp. 694-697 ◽

Cited By ~ 12

Author(s):

Fujiwara Hirokazu ◽

Masaki Konishi ◽

T. Ohnishi ◽

T. Nakamura ◽

Kimimori Hamada ◽

...

Keyword(s):

Dislocation Density ◽

Leakage Current ◽

Surface Defects ◽

High Yield ◽

Threading Dislocation ◽

Electrical Characteristics ◽

Large Area ◽

Low Leakage ◽

Low Leakage Current ◽

Threading Dislocation Density

The impacts of threading dislocations, surface defects, donor concentration, and schottky Schottky barrier height on the reverse IV characteristic of silicon carbide (SiC) junction barrier schottky Schottky (JBS) diodes were investigated. The 100 A JBS diodes were fabricated on 4H-SiC 3-inch N-type wafers with two types of threading dislocation density. The typical densities are were 0.2×104 and 3.8×104 cm-2, respectively. The improvement of vIt was found that variations in the leakage current and the high yield of large area JBS diodes werecould be were obtained improved by using a wafer with a low threading dislocation density. In the range of low leakage current, the investigation shows showed a correlation between leakage current and threading dislocation density.

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ZnO varistors with high voltage gradient and low leakage current by doping rare-earth oxide

Science in China Series E ◽

10.1007/s11431-008-0085-x ◽

2008 ◽

Vol 51 (6) ◽

pp. 693-701 ◽

Cited By ~ 35

Author(s):

JinLiang He ◽

Jun Hu ◽

YuanHua Lin

Keyword(s):

Rare Earth ◽

Leakage Current ◽

High Voltage ◽

Rare Earth Oxide ◽

Voltage Gradient ◽

Low Leakage ◽

Low Leakage Current ◽

Zno Varistors

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1200-V JBS Diodes with Low Threshold Voltage and Low Leakage Current

Materials Science Forum ◽

10.4028/www.scientific.net/msf.600-603.939 ◽

2008 ◽

Vol 600-603 ◽

pp. 939-942 ◽

Cited By ~ 8

Author(s):

Takeo Yamamoto ◽

Jun Kojima ◽

Takeshi Endo ◽

Eiichi Okuno ◽

Toshio Sakakibara ◽

...

Keyword(s):

Leakage Current ◽

Schottky Diode ◽

Threshold Voltage ◽

Reverse Bias ◽

Electrical Characteristics ◽

Low Leakage ◽

Forward Current ◽

Low Leakage Current ◽

Low Threshold ◽

Power Application

4H-SiC SBDs have been developed by many researchers and commercialized for power application devices in recent years. At present time, the issues of an SiC-SBD are lower on-state current and a relatively larger-leakage current at the reverse bias than Si-PN diodes. A JBS (Junction Barrier Schottky) diode was proposed as a structure to realize a lower leakage current. We simulated the electrical characteristics of JBS diodes, where the Schottky electrode was made of molybdenum in order to optimize its performance. We fabricated JBS diodes based on the simulation with a diameter of 3.9mm (11.9 mm2). The JBS diode has a lower threshold voltage of 0.45 V, a large forward current of 40 A at Vf = 2.5V and a high breakdown voltage of 1660 V. Furthermore, the leakage current at 1200 V was remarkably low (Ir = 20 nA).

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Effect of Ba Addition on Electrical Characteristics of Bi-Based ZnO Varistors

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.445.241 ◽

2010 ◽

Vol 445 ◽

pp. 241-244 ◽

Cited By ~ 6

Author(s):

Ai Fukumori ◽

Masayuki Takada ◽

Yuji Akiyama ◽

Yuuki Sato ◽

Shinzo Yoshikado

Keyword(s):

Grain Size ◽

Grain Growth ◽

Breakdown Voltage ◽

Electrical Characteristics ◽

Zno Varistor ◽

Electrical Degradation ◽

Poor Tolerance ◽

Zno Varistors ◽

Molten Phase

With the goal of fabricating low-breakdown-voltage varistors, the effect of adding Ba to ZnO varistors on the ZnO grain size was investigated. Grain growth of ZnO could be markedly promoted by adding both Ba and Bi. The maximum grain size was approximately 150 μm and the minimum varistor voltage was approximately 12 V/mm. However, it had relatively poor tolerance characteristics for electrical degradation. It is speculated that when adding both Ba and Bi to a Mn–Co-added ZnO varistor, it is necessary to form the molten phases of Ba and Bi to promote grain growth of ZnO. It is also conjectured that the growth of ZnO grains is not promoted when Ba and Bi do not coexist in the molten phase because Ba forms compounds with Mn independently with the addition of small amounts of Bi.

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Microchemistry of ZnO Varistors

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133102 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1694-1695

Author(s):

K. K. Soni ◽

J. Hwang ◽

V. P. Dravid ◽

T. O. Mason ◽

R. Levi-Setti

Keyword(s):

Grain Boundaries ◽

Multiple Roles ◽

Grain Boundary Engineering ◽

Ion Microprobe ◽

Dopant Distribution ◽

Important Ingredient ◽

Zno Varistor ◽

Zno Varistors ◽

Zno Powder ◽

The University

ZnO varistors are made by mixing semiconducting ZnO powder with powders of other metal oxides e.g. Bi2O3, Sb2O3, CoO, MnO2, NiO, Cr2O3, SiO2 etc., followed by conventional pressing and sintering. The non-linear I-V characteristics of ZnO varistors result from the unique properties that the grain boundaries acquire as a result of dopant distribution. Each dopant plays important and sometimes multiple roles in improving the properties. However, the chemical nature of interfaces in this material is formidable mainly because often trace amounts of dopants are involved. A knowledge of the interface microchemistry is an essential component in the ‘grain boundary engineering’ of materials. The most important ingredient in this varistor is Bi2O3 which envelopes the ZnO grains and imparts high resistance to the grain boundaries. The solubility of Bi in ZnO is very small but has not been experimentally determined as a function of temperature.In this study, the dopant distribution in a commercial ZnO varistor was characterized by a scanning ion microprobe (SIM) developed at The University of Chicago (UC) which offers adequate sensitivity and spatial resolution.

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