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Limited By:	Subject = Interface states;

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Displaying Results 1 - 7 of 7 on page 1 of 1

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An investigation of border traps and interface states in high-k/InGaAs metal-oxide-semiconductor systems (2017)

Lin, Jun

An investigation of border traps and interface states in high-k/InGaAs metal-oxide-semiconductor systems (2017)

Lin, Jun

Abstract:

One approach to saving energy in metal-oxide-semiconductor field effect transistors (MOSFETs) is to replace SiO2/Si structure with high dielectric constant (high-k) oxides on high mobility channel materials (e.g. InGaAs), which have the potential to achieve a comparable on current and operating frequency to silicon, but at a reduced supply voltage. In this thesis, investigation into border traps (or charge trapping) and interface states, both of which can induce device instability, in HfO2/InGaAs and Al2O3/InGaAs metal-oxidesemiconductor (MOS) structures was carried out with an emphasis on the characterization of border traps using capacitance-voltage (C-V) hysteresis measurement. The charge trapping is observed to be mainly a reversible process. The trapped charge is predominantly localized as a sheet charge near/at the high-k/InGaAs interfacial layer (~1nm), which can contain native oxides of InGaAs. The engineering of the high-k/InGaAs interface is therefore the key to reducing C...

http://hdl.handle.net/10468/5349

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Analysis of electron mobility in HfO2/TiN gate metal-oxide-semiconductor field effect transistors: The influence of HfO2 thickness, temperature, and oxide charge (2009)

Negara, Muhammad A.; Cherkaoui, Karim; Hurley, Paul K.; Young, C. D.; Majhi, P.; Tsai, ...

Analysis of electron mobility in HfO2/TiN gate metal-oxide-semiconductor field effect transistors: The influence of HfO2 thickness, temperature, and oxide charge (2009)

Negara, Muhammad A.; Cherkaoui, Karim; Hurley, Paul K.; Young, C. D.; Majhi, P.; Tsai, W.; Bauza, D.; Ghibaudo, G.

Abstract:

We report a new analysis of electron mobility in HfO2/TiN gate metal-oxide-semiconductor field effect transistors (MOSFETs) by investigating the influence of HfO2 thickness (1.6-3 nm), temperature (50-350 K), and oxide charge (similar to 1x10(11)-8x10(12) cm(-2)) in the high inversion charge region. The fixed oxide charge and interface state densities are deliberately increased using negative-bias-temperature stress, allowing the determination of the Coulomb scattering term as a function of temperature for various oxide charge levels. The temperature dependence of the Coulomb scattering term is consistent with the case of a strongly screened Coulomb potential. Using the experimentally determined temperature dependence of Coulomb scattering term, a model is developed for the electron mobility, including the effects oxide charge (mu(C)), high-k phonon (mu(Ph-Hk)), silicon phonon (mu(Ph-Si)), and surface roughness scattering (mu(SR)). The model provides an accurate description of the e...

http://hdl.handle.net/10468/4217

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Electron energy band alignment at the (100)Si/MgO interface (2010)

Afanas'ev, V. V.; Stesmans, A.; Cherkaoui, Karim; Hurley, Paul K.

Electron energy band alignment at the (100)Si/MgO interface (2010)

Afanas'ev, V. V.; Stesmans, A.; Cherkaoui, Karim; Hurley, Paul K.

Abstract:

The electron energy band diagram at the (100)Si/MgO interface is characterized using internal photoemission of electrons and holes from Si into the oxide. For the as-deposited amorphous MgO the interface barriers correspond to a band gap width of 6.1 eV, i.e., much lower than the conventionally assumed bulk crystal value (7.83 eV). The annealing-induced crystallization of MgO mostly affects the energy of the valence band while the conduction band bottom retains its energy position at 3.37 +/- 0.05 eV above the top of the silicon valence band.(C) 2010 American Institute of Physics. (doi:10.1063/1.3294328)

http://hdl.handle.net/10468/4347

Marked Mark

Profiling border-traps by TCAD analysis of multifrequency CV-curves in Al2O3/InGaAs stacks (2018)

Caruso, Enrico; Lin, Jun; Burke, K. F.; Cherkaoui, Karim; Esseni, David; Gity, Farzan; ...

Profiling border-traps by TCAD analysis of multifrequency CV-curves in Al2O3/InGaAs stacks (2018)

Caruso, Enrico; Lin, Jun; Burke, K. F.; Cherkaoui, Karim; Esseni, David; Gity, Farzan; Monaghan, Scott; Palestri, Pierpaolo; Hurley, Paul K.; Selmi, Luca

Abstract:

This paper reports physics based TCAD simulations of multi-frequency C-V curves of In0.53Ga0.47As MOSCAPs including the AC response of the border traps. The calculations reproduce the experimental inversion and accumulation capacitance versus frequency, and provide a means to profile the space and energy density of states of border traps. A sensitivity analysis of the results to border traps' distribution is carried out changing the trap volume and the oxide capacitance.

http://hdl.handle.net/10468/7161

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Properties of homo- and hetero-Schottky junctions from first principle calculations (2018)

Greer, James C.; Blom, Anders; Ansari, Lida

Properties of homo- and hetero-Schottky junctions from first principle calculations (2018)

Greer, James C.; Blom, Anders; Ansari, Lida

Abstract:

Electronic structure calculations for a homo-material semimetal (thick Sn)/semiconductor (thin Sn) heterodimensional junction and two conventional metal (Ag or Pt)/silicon hetero-material junctions are performed. Charge distributions and local density of states are examined to compare the physics of junctions formed by quantum confinement in a homo-material, heterodimensional semimetal junction with that of conventional Schottky hetero-material junctions. Relative contributions to the Schottky barrier heights are described in terms of the interface dipoles arising due to charge transfer at the interface and the effects of metal induced gap states extending into the semiconducting regions. Although the importance of these physical mechanisms vary for the three junctions, a single framework describing the junction energetics captures the behaviors of both the heterodimensional semimetal junction and the more conventional metal/semiconductor junctions.

http://hdl.handle.net/10468/9658

Marked Mark

Role of sulfur in vibration spectra and bonding and electronic structure of GeSi surfaces and interfaces (2016)

Hartnett, Mark C.

Role of sulfur in vibration spectra and bonding and electronic structure of GeSi surfaces and interfaces (2016)

Hartnett, Mark C.

Abstract:

A quantum mechanical density functional theory approach was used to investigate the structural atomic configuration, vibration mode frequencies and electronic structure of surfaces and interfaces using germanium. Initially, we investigated the H2S and H2Opassivated germanium surfaces. A supercell approach is used with the local density (LDA), generalized gradient (GGA) approximations and van der Waals (vdW) interactions. The frozen phonon method was used to calculate the vibrational mode frequencies of these surfaces. The calculated frequencies produce stretch, bond bending and wag modes. The differences between the functionals including vdW terms and the LDA or GGA are less than the differences between LDA and GGA for the vibrational mode frequencies. Some of these modes provide useful vibrational signatures of bonding of both sulfur and oxygen on germanium surfaces, which may be compared with vibrational spectroscopy measurements. A bare germanium surface is bonded to a bare silic...

http://hdl.handle.net/10468/3665

Marked Mark

The nature of interfaces and charge trapping sites in photocatalytic mixed-phase TiO2 from first principles modeling (2015)

Garcia, Juan C.; Nolan, Michael; Deskins, N. Aaron

The nature of interfaces and charge trapping sites in photocatalytic mixed-phase TiO2 from first principles modeling (2015)

Garcia, Juan C.; Nolan, Michael; Deskins, N. Aaron

Abstract:

Mixed phase rutile/anatase catalysts show increased reactivity compared with the pure phases alone. However, the mechanism causing this effect is not fully understood. The electronic properties of the interface and the relative energy of the electron in each phase play a key role in lowering the rate of recombination of electron hole pairs. Using density functional theory and the +U correction, we calculated the bands offsets between the phases taking into account the effect of the interface. Our model included several thousands atoms, and thus is a good representation of an interface between actual nanoparticles. We found rutile to have both higher conduction and valence band offsets than rutile, leading to an accumulation of electrons in the anatase phase accompanied by hole accumulation in the rutile phase. We also probed the electronic structure of our heterostructure and found a gap state caused by electrons localized in undercoordinated Ti atoms which were present within the i...

http://hdl.handle.net/10468/5203

Displaying Results 1 - 7 of 7 on page 1 of 1