Measurement of Fowler-Nordheim tunneling currents in MOS structures under charge trapping conditions

The interface between the gate oxide and silicon carbide (SiC) has a strong influence on the performance and reliability of SiC MOSFETs and thus, requires special attention. In order to reduce charge trapping at the interface, post oxidation anneals (POAs) are conventionally applied. However, these anneals do not only influence the device performance, such as mobility and on-resistance, but also the gate oxide reliability. We study the oxide tunneling mechanisms of NH3 annealed 4H-SiC trench MOSFET test structures and compare them to devices which received a NO POA. We show that 3 different mechanisms, namely trap assisted tunneling (TAT), Fowler-Nordheim (FN) tunneling and charge trapping are found for NH3 annealed MOS structures whereas only FN-tunneling is observed in NO annealed devices.The tunneling barrier suggest a trap level with an effective activation energy of 382 meV to enable TAT.

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Nanoscale metal transistor control of Fowler–Nordheim tunneling currents through 16 nm insulating channel

Journal of Applied Physics ◽

10.1063/1.370104 ◽

1999 ◽

Vol 85 (9) ◽

pp. 6912-6916 ◽

Cited By ~ 18

Author(s):

Kouji Fujimaru ◽

Ryouta Sasajima ◽

Hideki Matsumura

Keyword(s):

Tunneling Currents ◽

Nordheim Tunneling

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Microroughness at the Si/SiO2 Interface from Pre-Oxidation Annealing, Measured Using Quantum Oscillations in Fowler-Nordheim Tunneling Currents

MRS Proceedings ◽

10.1557/proc-280-139 ◽

1992 ◽

Vol 280 ◽

Author(s):

J. C. Poler ◽

K. K. McKay ◽

E. A. Irene

Keyword(s):

Gate Dielectrics ◽

Interface Roughness ◽

Quantum Oscillation ◽

Interfacial Region ◽

Mos Capacitors ◽

Quantum Oscillations ◽

High Temperature Anneal ◽

Afm Imaging ◽

Tunneling Currents ◽

Nordheim Tunneling

ABSTRACTAs design rules shrink to conform with ULSI device dimensions, gate dielectrics for MOSFET structures are required to be scaled to even thinner proportions. Upon scaling the gate oxides below ∼60Å some properties of the device, such as interface roughness, that are negligible for thicker films become critical and must be evaluated. Microroughness at the interface of ultrathin MOS capacitors has been shown to degrade these devices.We are studying the interfacial region of ∼50Å SiO2 on Si using the quantum oscillations in Fowler-Nordheim tunneling currents. The oscillations are sensitive to the electron potential and abruptness of the film and its interfaces. In particular, inelastic scattering and/or thickness inhomogeneities in the film will reduce the amplitude of the oscillations. We are using the amplitude of the oscillations to examine the degree of microroughness at the interface that results from a pre-oxidation high temperature anneal in an inert ambient containing various amounts of H2O. Preliminary AFM imaging has shown correlations supporting our microroughness interpretation of the quantum oscillation amplitudes.

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Characterization of the Si/SiO2 Interfere Morphology from Quantum Oscillations in Fowler-Nordheim Tunneling Currents

10.21236/ada265149 ◽

1993 ◽

Author(s):

J. C. Poler ◽

K. K. McKay ◽

E. A. Irene

Keyword(s):

Quantum Oscillations ◽

Tunneling Currents ◽

Nordheim Tunneling

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Electrical Characterization of High-k Dielectrics by Means of Flat-Band Voltage Transient Recording

MRS Proceedings ◽

10.1557/proc-0996-h07-11 ◽

2007 ◽

Vol 996 ◽

Author(s):

Salvador Duenas ◽

Helena Castán ◽

Héctor García ◽

Luis Bailón ◽

Kaupo Kukli ◽

...

Keyword(s):

Electric Fields ◽

Electrical Characterization ◽

Charge Trapping ◽

Atomic Layer ◽

Localized States ◽

Oxide Semiconductor ◽

Flat Band ◽

Flat Band Voltage ◽

High K ◽

Mos Structures

AbstractWe have carried out a comparison between flat-band transients displayed in metal-oxide-semiconductor (MOS) structures fabricated on several atomic layer deposited (ALD) high-k dielectric films: HfO2, ZrO2, Al2O3, Ta2O5, TiO2, and Gd2O3. The gate voltage as a function of time is recorded while keeping constant the capacitance at the initial flat band condition (CFB). Since samples are in darkness, under no electric fields and no charge-injection conditions, transients must be due to charge trapping of localized states produced by electrons (holes) coming from the semiconductor by tunnelling. The process is assisted by phonons and it is therefore thermally activated. The temperature-transient amplitude relation follows an Arrhenius plot which provides the thermal activation energy of soft-optical phonons. Finally, we describe the dependencies of the flat-band voltage on the setup bias history (accumulation or inversion) and the hysteresis sign (clockwise or counter-clockwise) of the capacitance-voltage (C-V) characteristics of MOS structures.

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Analysis of the effects of constant‐current Fowler–Nordheim‐tunneling injection with charge trapping inside the potential barrier

Journal of Applied Physics ◽

10.1063/1.349222 ◽

1991 ◽

Vol 70 (7) ◽

pp. 3712-3720 ◽

Cited By ~ 33

Author(s):

J. A. Lopez‐Villanueva ◽

J. A. Jimenez‐Tejada ◽

P. Cartujo ◽

J. Bausells ◽

J. E. Carceller

Keyword(s):

Potential Barrier ◽

Charge Trapping ◽

Constant Current ◽

Tunneling Injection ◽

Nordheim Tunneling

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Charge Trapping Memory Cell of TANOS (Oxide-SiN-Al2O3-TaN) Structure Erased by Fowler-Nordheim Tunneling of Holes

MRS Proceedings ◽

10.1557/proc-0933-g02-09 ◽

2006 ◽

Vol 933 ◽

Author(s):

Chang-Hyun Lee ◽

Changseok Kang ◽

Yoocheol Shin ◽

Jaesung Sim ◽

Jongsun Sel ◽

...

Keyword(s):

Energy Level ◽

Threshold Voltage ◽

Charge Trapping ◽

Memory Cell ◽

Floating Gate ◽

Hole Trap ◽

Hole Trapping ◽

High K ◽

Charge Trapping Memory ◽

Nordheim Tunneling

ABSTRACTWe present the TANOS (Si-Oxide-SiN-Al2O3-TaN) cell with 40 Å-thick tunnel oxide erased by Fowler-Nordheim (FN) tunneling of hole. Thanks to introducing high-k dielectrics, alumina (Al2O3) as a blocking oxide, the erase threshold voltage can be maintained to less than - 3.0 V, meaning hole-trapping in SiN. We extracted the nitride trap densities of electron and hole for the TANOS cell. It is demonstrated that the TANOS structure is very available to investigate the trap density with shallower energy. The energy level of hole trap (1.28 eV) is found to be deeper than that of electron (0.8 eV). As the cycling stress is performed, persistent hole-trapping is observed unlike endurance characteristics of conventional floating-gate cell. The hole trapping during the cycling stress can be attributed to two possibilities. The injected holes are trapped in neutral trap of tunnel oxide and residue of holes which is not somewhat compensated by injected electrons may be accumulated in SiN. It is demonstrated the erase operation of the TANOS cell is governed by Fowler-Nordheim tunneling of hole due to the field concentration across the tunnel oxide.

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Stress Induced Increased Low Level Leakage in Thin Oxides

MRS Proceedings ◽

10.1557/proc-284-319 ◽

1992 ◽

Vol 284 ◽

Cited By ~ 5

Author(s):

D. J. Dumin ◽

J. R. Maddux ◽

D.-P. Wong

Keyword(s):

Schottky Barrier ◽

Stress Measurement ◽

Tunneling Current ◽

Schottky Emission ◽

Leakage Currents ◽

Gate Oxides ◽

Low Level ◽

Tunneling Currents ◽

Best Fit ◽

Nordheim Tunneling

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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