Stress Induced Increased Low Level Leakage in Thin Oxides

ABSTRACTIt has been observed that the low-level, pre-tunneling currents through thin gate oxides increased after the oxides had been stressed at high voltages. The number of traps inside of the oxide generated by the stress has been shown to increase as the 1/3 power of the fluence that had passed through the oxide during the stress. The increases in the low-level, pre-tunneling currents have been shown to be proportional to the number of stress generated traps in the oxide and not to the fluence during the stress. The voltage dependences of the excess low-level leakage currents were stress and measurement polarity dependent. Attempts have been made to fit the voltage dependences of the excess low-level currents to Fowler-Nordheim tunneling, Frenkel-Poole conduction or Schottky barrier lowering. The increase in the portion of the low-level, pre-tunneling current that was not dependent on stress/measurement polarity sequence was best fit using Schottky emission currents. The model that has been developed to describe the increases in the low-level currents has centered on trap-assisted currents through the oxides.

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Electrical Characteristics of Large Chip-Size 3.3 kV SiC-JBS Diodes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.740-742.881 ◽

2013 ◽

Vol 740-742 ◽

pp. 881-886 ◽

Cited By ~ 8

Author(s):

Hiroyuki Okino ◽

Norifumi Kameshiro ◽

Kumiko Konishi ◽

Naomi Inada ◽

Kazuhiro Mochizuki ◽

...

Keyword(s):

Electric Field ◽

Schottky Barrier ◽

Leakage Current ◽

Reverse Current ◽

Tunneling Current ◽

Leakage Currents ◽

Reverse Leakage Current ◽

Low Leakage ◽

Chip Size ◽

Barrier Metal

The reduction of reverse leakage currents was attempted to fabricate 4H-SiC diodes with large current capacity for high voltage applications. Firstly diodes with Schottky metal of titanium (Ti) with active areas of 2.6 mm2 were fabricated to investigate the mechanisms of reverse leakage currents. The reverse current of a Ti Schottky barrier diode (SBD) is well explained by the tunneling current through the Schottky barrier. Then, the effects of Schottky barrier height and electric field on the reverse currents were investigated. The high Schottky barrier metal of nickel (Ni) effectively reduced the reverse leakage current to 2 x 10-3 times that of the Ti SBD. The suppression of the electric field at the Schottky junction by applying a junction barrier Schottky (JBS) structure reduced the reverse leakage current to 10-2 times that of the Ni SBD. JBS structure with high Schottky barrier metal of Ni was applied to fabricate large chip-size SiC diodes and we achieved 30 A- and 75 A-diodes with low leakage current and high breakdown voltage of 4 kV.

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Tunneling Currents in Nanoscale high-κ MOS Structures

MRS Proceedings ◽

10.1557/opl.2011.385 ◽

2011 ◽

Vol 1292 ◽

Author(s):

Andrés Vercik

Keyword(s):

Integrated Circuits ◽

Power Dissipation ◽

Inversion Layer ◽

Tunneling Current ◽

Semiconductor Surface ◽

Leakage Currents ◽

Additional Layer ◽

Promising Strategy ◽

Tunneling Currents ◽

Mos Structures

ABSTRACTFurther improvements of integrated circuits depend on the continuous downscaling of MOSFET´s, well beyond the limits for which direct tunneling currents are acceptable. These leakage currents affect both the stand-by power dissipation and the formation of the inversion layer ate the semiconductor surface, i.e., the channel formation. The most promising strategy to overcome this problem is the use of high-κ insulator in substitution of or as an additional layer on the traditional silicon dioxide. The aim of this work is using a recently developed theory to describe tunneling from inversion layers for high-κ insulators or stacks and analyze the effects of tunneling current on the thermal equilibrium in these cases.

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The Effect of Roughness Features on Mos Surface Electric Field and Fowler-Nordheim Tunneling Behavior

MRS Proceedings ◽

10.1557/proc-473-175 ◽

1997 ◽

Vol 473 ◽

Author(s):

Heng-Chih Lin ◽

Edwin C. Kan ◽

Toshiaki Yamanaka ◽

Simon J. Fang ◽

Kwame N. Eason ◽

...

Keyword(s):

Electric Field ◽

Three Dimensional ◽

Tunneling Current ◽

Gate Oxide ◽

Oxide Thickness ◽

Interface Roughness ◽

Normal Electric Field ◽

Surface Electric Field ◽

Tunneling Behavior ◽

Nordheim Tunneling

ABSTRACTFor future CMOS GSI technology, Si/SiO2 interface micro-roughness becomes a non-negligible problem. Interface roughness causes fluctuations of the surface normal electric field, which, in turn, change the gate oxide Fowler-Nordheim tunneling behavior. In this research, we used a simple two-spheres model and a three-dimensional Laplace solver to simulate the electric field and the tunneling current in the oxide region. Our results show that both quantities are strong functions of roughness spatial wavelength, associated amplitude, and oxide thickness. We found that RMS roughness itself cannot fully characterize surface roughness and that roughness has a larger effect for thicker oxide in terms of surface electric field and tunneling behavior.

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APPLICATION OF EPITAXIAL UNIPOLAR BARRIERS TO REDUCE NOISE CURRENTS IN PHOTODETECTORS

International Journal of High Speed Electronics and Systems ◽

10.1142/s0129156411006854 ◽

2011 ◽

Vol 20 (03) ◽

pp. 557-564

Author(s):

G. R. SAVICH ◽

J. R. PEDRAZZANI ◽

S. MAIMON ◽

G. W. WICKS

Keyword(s):

Leakage Current ◽

Surface Passivation ◽

Leakage Currents ◽

Type Region ◽

Surface Leakage Current ◽

Unipolar Barrier ◽

Trap Assisted Tunneling ◽

Assisted Tunneling ◽

Tunneling Currents ◽

Surface Leakage

Tunneling currents and surface leakage currents are both contributors to the overall dark current which limits many semiconductor devices. Surface leakage current is generally controlled by applying a post-epitaxial passivation layer; however, surface passivation is often expensive and ineffective. Band-to-band and trap assisted tunneling currents cannot be controlled through surface passivants, thus an alternative means of control is necessary. Unipolar barriers, when appropriately applied to standard electronic device structures, can reduce the effects of both surface leakage and tunneling currents more easily and cost effectively than other methods, including surface passivation. Unipolar barriers are applied to the p -type region of a conventional, MBE grown, InAs based pn junction structures resulting in a reduction of surface leakage current. Placing the unipolar barrier in the n -type region of the device, has the added benefit of reducing trap assisted tunneling current as well as surface leakage currents. Conventional, InAs pn junctions are shown to exhibit surface leakage current while unipolar barrier photodiodes show no detectable surface currents.

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