A method for measuring barrier heights, metal work functions and fixed charge densities in metal/SiO2/Si capacitors

2002 ◽  
Vol 80 (25) ◽  
pp. 4858-4860 ◽  
Author(s):  
Sufi Zafar ◽  
Cyril Cabral ◽  
R. Amos ◽  
A. Callegari
Keyword(s):  
Fixed Charge ◽  
Charge Densities ◽  
Barrier Heights ◽  
Work Functions ◽  
Metal Work

Barrier heights of Schottky contacts on strained AlGaN/GaN heterostructures: Determination and effect of metal work functions

2003 ◽  
Vol 82 (24) ◽  
pp. 4364-4366 ◽  
Author(s):  
Zhaojun Lin ◽  
Wu Lu ◽  
Jaesun Lee ◽  
Dongmin Liu ◽  
Jeffrey S. Flynn ◽  
...  
Keyword(s):  
Schottky Contacts ◽  
Barrier Heights ◽  
Work Functions ◽  
Metal Work

Low Schottky Barrier on N-Type Si for N-Channel Schottky Source/Drain MOSFETs

2003 ◽  
Vol 765 ◽  
Author(s):  
Meng Tao ◽  
Darshak Udeshi ◽  
Shruddha Agarwal ◽  
Nasir Basit ◽  
Eduardo Maldonado ◽  
...  
Keyword(s):  
Schottky Barrier ◽  
Atomic Scale ◽  
Barrier Heights ◽  
Metal Work Function ◽  
Metal Silicides ◽  
The Common ◽  
Work Functions ◽  
Metal Work ◽  
Density Of Interface States ◽  
The Ideal

AbstractSchottky source/drain (S/D) in Si-CMOS provide an alternative to current approaches in S/D, channel, and gate-stack engineering. The Schottky S/D PMOS has been demonstrated at a number of university and industrial laboratories. The bottleneck for the Schottky S/D NMOS is the fact that none of the common metals or metal silicides has a low enough barrier height (~0.2 eV) on n-type Si. A method to produce low Schottky barriers on n-type Si with common metals including aluminum (Al) and chromium (Cr) is reported in this paper. The interface between metal and Si(100) is engineered at the atomic scale with a monolayer of selenium (Se) to reduce the density of interface states, and the engineered interface shows inertness to chemical and electronic processes at the interface. One consequence of this electronic inertness is that the Schottky barrier is now more dependent on the metal work function. Al and Cr both have work functions very close to the Si electron affinity. It is found that the Schottky barrier of Al on Se-engineered n-type Si(100) is 0.08 eV, and that of Cr is 0.26 eV. These numbers agree well with the ideal Schottky barrier heights for Al and Cr on n-type Si(100), but are significantly different from the barrier heights known for four decades for these metals on n-type Si(100). These results bring new hope for the Schottky S/D NMOS with a metal commonly used in the Si industry.

Passivation of Gaas by Novel P2S5/(NH4)2Sx Sulfurization Techniques

1992 ◽  
Vol 281 ◽  
Author(s):  
J. T. Hsieh ◽  
C. Y. Sun ◽  
H. L. Hwang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Passivation ◽  
Schottky Diodes ◽  
Lower Surface ◽  
State Density ◽  
Surface Band ◽  
Band Bending ◽  
Barrier Heights ◽  
Effective Barrier ◽  
Metal Work

ABSTRACTA new surface passivation technique using P2S5/(NH4)2S on GaAs was investigated, and the results are compared with those of the (NH4)2Sx treatment. With this new surface treatment, the effective barrier heights for both Al- and Au—GaAs Schottky diodes were found to vary with the metal work functions, which is a clear evidence of the lower surface state density. Results of I—V measurements show that P2S5/(NH4)2S—passivated diodes have lower reverse leakage current and higher effective barrier height than those of the (NH4)2Sx -treated ones. Auger Electron Spectroscopy, X—ray photoelectron spectroscopy and Raman scattering measurements were done to characterize the surfaces including their compositions and surface band bending. In this paper, interpretations on this novel passivation effect is also provided.

Trap-assisted tunnelling current in MIM structures

Open Physics ◽  
2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Juraj Racko ◽  
Miroslav Mikolášek ◽  
Ralf Granzner ◽  
Juraj Breza ◽  
Daniel Donoval ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Quantum Mechanical ◽  
Current Transport ◽  
Metal Insulator ◽  
Insulating Layer ◽  
New Model ◽  
Metal Insulator Metal ◽  
Work Functions ◽  
Metal Work ◽  
Tunnelling Current

AbstractA new model is presented of current transport in Metal Insulator Metal (MIM) structures by quantum mechanical tunnelling. In addition to direct tunnelling through an insulating layer, tunnelling via defects present in the insulating layer plays an important role. Examples of the influence of the material and thickness of the insulating layer, energy distribution of traps, and metal work functions are also provided.

scholarly journals Tuning of Metal Work Functions with Self-Assembled Monolayers

2005 ◽  
Vol 17 (5) ◽  
pp. 621-625 ◽  
Author(s):  
B. de Boer ◽  
A. Hadipour ◽  
M. M. Mandoc ◽  
T. van Woudenbergh ◽  
P. W. M. Blom
Keyword(s):  
Self Assembled Monolayers ◽  
Assembled Monolayers ◽  
Work Functions ◽  
Self Assembled ◽  
Metal Work

Influence of Metal Electrodes on the Ferroelectric Responses of Poly(vinylidene fluoride-trifluoroethylene) Copolymer Thin Films

2002 ◽  
Vol 734 ◽  
Author(s):  
Feng Xia ◽  
Q. M. Zhang
Keyword(s):  
Thin Films ◽  
Vinylidene Fluoride ◽  
Bias Field ◽  
Polarization Switching ◽  
Interface Effect ◽  
Metal Electrodes ◽  
Poly Vinylidene Fluoride ◽  
Work Functions ◽  
Metal Work ◽  
Bulk Effect

ABSTRACTFerroelectric polymer thin films have been investigated for applications such as sensors, MEMS, and memory devices, just name a few. In these thin film devices, it is anticipated that the interface effect will play an important role in determining the device performance. In this paper, we present the results of a recent study on the influence of metal electrodes on ferroelectric switching behavior of poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) polymer thin films. The results show that the influence of metal electrodes on the polarization response can be divided into two effects, the bulk effect and interface effect. The bulk effect manifests itself as the built-in bias field when metal electrodes with different work functions were used on the two surfaces of the P(VDF-TrFE) film. The interface effect is more complicated but is directly related to the metal work function. For a metal I/insulator (ferroelectric film)/metal II (MIM) sandwich structure in which the metal I and metal II possess different work functions, the low frequency polarization hysteresis loop shows asymmetric response (different switching fields). The polarization switching time also depends on whether the applied voltage is in parallel or anti-parallel to the built-in bias field. In the fast polarization switching process, it was observed that the interface effect plays a dominating role and the switching time is mainly limited by the charge injection from metal electrodes to the polymer film. For metal electrodes with higher work function, higher injection currents and hence faster polarization switching were observed. The results from I-V studies also show that the charge injection process is a Schottky type and the barrier height estimated from the temperature dependence of the I-V curves is consistent with the metal work functions used.

scholarly journals Effective reduction of fixed charge densities in germanium based metal-oxide-semiconductor devices

2011 ◽  
Vol 99 (5) ◽  
pp. 052906 ◽  
Author(s):  
Shaoren Deng ◽  
Qi Xie ◽  
Davy Deduytsche ◽  
Marc Schaekers ◽  
Dennis Lin ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Semiconductor Devices ◽  
Metal Oxide Semiconductor ◽  
Fixed Charge ◽  
Oxide Semiconductor ◽  
Charge Densities ◽  
Effective Reduction

Adsorption of self-assembled monolayer on Cu(111): First-principles study

2017 ◽  
Vol 31 (24) ◽  
pp. 1750198
Author(s):  
Jian Wang ◽  
Jiang-Tao Cheng ◽  
Shang-Yi Ma ◽  
Hong-De Wang
Keyword(s):  
Work Function ◽  
First Principles ◽  
Function Theory ◽  
Self Assembled Monolayer ◽  
Effective Technique ◽  
Adsorption Sites ◽  
Metal Work Function ◽  
Surface Adsorbates ◽  
Work Functions ◽  
Metal Work

The density function theory is used to explore the structures of alkyl-thiolate (RS, R=CH3, CF3) monolayer on the Cu(111) surface. By performing the total energy calculations for RS at three possible adsorption sites (fcc, hcp, bridge) with five different coverages (1/12, 1/9, 1/6, 1/4, 1/3), we obtained the stable adsorption configurations of the Cu–RS system. Especially, the effect of Van der Waals interaction on the adsorption configurations was studied by the DFT-D2 method. The work functions for Cu–RS (R=CH3, CF3) systems were calculated, we find that the CH3S adsorbed on the Cu(111) surface decreases the metal work function remarkably, and the work functions strongly depend on the coverage. In the case of the Cu–CF3S system, the results are just the opposite. Thus, controlling the kind and coverage of the surface adsorbates would be an effective technique to tune the work function of the metal.

Importance of Collagen Orientation and Depth-Dependent Fixed Charge Densities of Cartilage on Mechanical Behavior of Chondrocytes

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Rami K. Korhonen ◽  
Petro Julkunen ◽  
Wouter Wilson ◽  
Walter Herzog
Keyword(s):  
Extracellular Matrix ◽  
Articular Cartilage ◽  
Current Model ◽  
Fixed Charge ◽  
Solid Matrix ◽  
Pericellular Matrix ◽  
Collagen Network ◽  
Mechanical Environment ◽  
Collagen Orientation ◽  
Charge Densities

The collagen network and proteoglycan matrix of articular cartilage are thought to play an important role in controlling the stresses and strains in and around chondrocytes, in regulating the biosynthesis of the solid matrix, and consequently in maintaining the health of diarthrodial joints. Understanding the detailed effects of the mechanical environment of chondrocytes on cell behavior is therefore essential for the study of the development, adaptation, and degeneration of articular cartilage. Recent progress in macroscopic models has improved our understanding of depth-dependent properties of cartilage. However, none of the previous works considered the effect of realistic collagen orientation or depth-dependent negative charges in microscopic models of chondrocyte mechanics. The aim of this study was to investigate the effects of the collagen network and fixed charge densities of cartilage on the mechanical environment of the chondrocytes in a depth-dependent manner. We developed an anisotropic, inhomogeneous, microstructural fibril-reinforced finite element model of articular cartilage for application in unconfined compression. The model consisted of the extracellular matrix and chondrocytes located in the superficial, middle, and deep zones. Chondrocytes were surrounded by a pericellular matrix and were assumed spherical prior to tissue swelling and load application. Material properties of the chondrocytes, pericellular matrix, and extracellular matrix were obtained from the literature. The loading protocol included a free swelling step followed by a stress-relaxation step. Results from traditional isotropic and transversely isotropic biphasic models were used for comparison with predictions from the current model. In the superficial zone, cell shapes changed from rounded to elliptic after free swelling. The stresses and strains as well as fluid flow in cells were greatly affected by the modulus of the collagen network. The fixed charge density of the chondrocytes, pericellular matrix, and extracellular matrix primarily affected the aspect ratios (height/width) and the solid matrix stresses of cells. The mechanical responses of the cells were strongly location and time dependent. The current model highlights that the collagen orientation and the depth-dependent negative fixed charge densities of articular cartilage have a great effect in modulating the mechanical environment in the vicinity of chondrocytes, and it provides an important improvement over earlier models in describing the possible pathways from loading of articular cartilage to the mechanical and biological responses of chondrocytes.

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