Magnitude Of Leakage Current Research Articles

Study of Stress-Induced Leakage Current in Thin Oxides Stressed by Corona Charging in Air: Relationship to GOI Defects

ABSTRACTCorona charging in air combined with non-contact oxide charge measurement with a contact potential difference probe provides an unique possibility for fast monitoring of electron tunneling characteristics without preparation of MOS capacitors. It has also been found tha corona charging of thin oxides in the tunneling range is very effective in generating stressinduced leakage current. In this work we demonstrate the sensitivity of the corona stressinduced leakage current magnitude to gate oxide integrity defect density. The experimenta results cover three of the most common gate oxide integrity defects, namely: 1 – the defect induced by heavy metals (Fe.Cu) at a practically important low concentration range of 1×1010 to 1×1011 atoms/cm3: 2 – the defects originating from interface roughness and 3–the defects related to crystal originated particles.At low corona stress fluence, these defects play no role in the tunneling characteristics which follow ideal Fowler-Nordheim characteristics for oxides 50Å or thicker and a contribution from a direct tunneling current for thinner oxides. At high corona stress fluences, gate oxide integrity defects control the magnitude of stress-induced leakage current measured at constan oxide field. It is suggested that the gate oxide integrity role is associated with the enhanced rate of the trap generation during stress. It is noted that the present findings employ a novel methodology for gate oxide integrity monitoring based on corona charging and contact potential difference measurement.

Design considerations and experimental analysis of high-voltage SiC Schottky barrier rectifiers

Practical design of high-voltage SiC Schottky rectifiers requires an understanding of the device physics that affect the key performance parameters. Forward characteristics of SiC Schottky rectifiers follow thermionic emission theory and are relatively well understood. However, the reverse characteristics are not well understood and have not been experimentally investigated in-depth. In this paper we report the analysis and experimental results of both the forward and reverse characteristics of high-voltage SiC Schottky rectifiers. Ti and Ni Schottky rectifiers with boron implant edge termination were fabricated on n-type 4H SiC samples. Ni Schottky rectifiers fabricated on a 13-/spl mu/m thick 3.5/spl times/10/sup 15/ cm/sup -3/ epilayer have a current density of 100 A/cm/sup 2/ at approximately 2 V forward bias and a reverse leakage current density of less than 0.1 A/cm/sup 2/ at a reverse bias of 1720 V. The reverse leakage current is observed to depend on device area, Schottky barrier height, electric field at the metal-semiconductor interface, and temperature (a decreasing temperature dependence with increasing reverse bias). In addition. the reverse leakage current magnitude is larger and the electric field dependence is stronger than predicted by thermionic emission and image-force barrier height lowering. This suggests the reverse leakage current is due to a combination of thermionic field emission and field emission.

In vivo measurements of leakage current during transurethral resection.

To estimate the magnitude of leakage current during transurethral resection 3 tape electrodes were applied to the penis and connected to earth through 50 kohm resistances (in order to minimize the current drawn from the neutral plate). A total of maximally 4 mAmp was measured through these electrodes. The measurements were independent of the concentration of hemoglobin in the irrigation fluid, the lubricant applied or whether a Teflon coated shaft was used. The maximum current of 4 mAmp has to pass an area as small as 0.1 mm2 for 0.2 sec in order to produce a second degree burn in the urethra. It is thus concluded that from an electrical point of view transurethral resection is a safe procedure not liable to give rise to any urethral burns. Using an isolated Teflon coated shaft has thus no practical value in reducing the leakage current.

Influence of thermal oxide on leakage current for Pb-alloy Josephson junctions

The effects of thermal oxide on leakage current of rf-plasma oxidized Pb-In-Au alloy Josephson junctions are examined. The leakage current is small in junctions with thermal oxide grown at low oxygen pressure and for a long period. Current-voltage characteristics at low temperature show that the leakage current magnitude is closely related to the magnitude of the current steps at the gap voltages of electrode materials. Furthermore, optical property investigations of the oxide show that leakage current decreases with a decrease in the oxide absorption coefficients, which are correlated to carrier density. Based on these experimental data, a leakage current model is proposed for Pb-alloy junctions. This model shows that the tunneling current between superconductor and normal metal regions in the oxide barrier causes leakage current.

Field Measurements of Leakage Current in insulaing Gloves

The paper gives results from field measurements of leakage current from Class IV insulating gloves for a range of supply voltage up to 40 kV. The test set-up simulated a contact of an insulating glove with a line. The results have shown that the magnitude of the glove leakage current is dependent on how close is the work location to a ground such as a wood pole or a neutral wire. Also, the paper shows that a large increase in the glove leakage current can occur when a worker wearing insulating gloves stands on an insulating support and then the support is grounded. For example, at 9.6 kV the glove leakage current was measured at 220μ A when the mannequin representing a worker was placed on an insulating support, and 2,350μ or some ten times higher when the support was grounded. The test results have an important bearing on the safety of using insulating gloves during live line maintenance.

Cw argon laser annealing of anodic oxide on GaAs

Anodic oxide films (850±50 Å thick) grown on n+(100) bulk GaAs were subjected to selective area annealing using a cw argon laser operating at an output power of 1.2 W. Capacitance-voltage (C-V) measurements performed on Al-anodic oxide-GaAs MOS capacitor structures show that laser-annealed capacitor dots have greatly reduced field-induced hysteresis effects in their capacitance-voltage characteristics compared to the unannealed ones. The oxide leakage current also shows a significant improvement—the leakage current magnitude of MOS capacitors in laser-annealed oxide island is over four orders of magnitude less than the oxide region which was not exposed to the laser radiation. Dielectric breakdown measurement indicates that laser-annealed capacitors have considerably higher breakdown voltages, about a factor of 2 higher than the unannealed capacitors.