scholarly journals Новый механизм реализации омических контактов

2018 ◽  
Vol 52 (1) ◽  
pp. 138
Author(s):  
А.В. Саченко ◽  
А.Е. Беляев ◽  
Р.В. Конакова
Keyword(s):  
Barrier Height ◽  
Ohmic Contacts ◽  
Contact Potential Difference ◽  
Surface States ◽  
Semiconductor Interface ◽  
Contact Potential ◽  
Semiconductor Doping ◽  
Semiconductor Contacts ◽  
Contact Barrier ◽  
Semiconductor Contact

AbstractAnalysis of the contact-barrier height taking into account the distribution of surface states along coordinate x perpendicular to the insulator–semiconductor interface is performed for metal–semiconductor contacts with a dielectric gap. It is shown that taking into account the spatial dependence of the density of surface states at rather high semiconductor doping levels leads to a substantial decrease in the barrier height, which promotes the realization of ohmic contacts. It is established that the smaller the metal–semiconductor contact potential difference ϕ_ ms is, the stronger the effect of barrier-height lowering. If ϕ_ ms is negative, this effect can lead to potential sign reversal, i.e., to the realization of an enrichment layer in the space-charge region of the semiconductor even at a high density of surface states. This in turn promotes the manifestation of an anomalous dependence of the contact resistivity on temperature; the resistivity increases with an increase in temperature.

scholarly journals Charge Separation by Collision of Ice Particles on Metals: Electronic Surface States

1978 ◽  
Vol 21 (85) ◽  
pp. 547-557 ◽  
Author(s):  
Othmar Buser ◽  
Claude Jaccard
Keyword(s):  
Electric Field ◽  
Charge Separation ◽  
Contact Potential Difference ◽  
Surface States ◽  
Metal Target ◽  
Contact Potential ◽  
Ice Particles ◽  
Air Speed ◽  
Electronic Surface ◽  
Transfer Probability

Abstract The charge separation of ice particles colliding with metals was investigated in a wind tunnel (air speed 10 m/s) at a temperature of —45°C for different metals as a function of an applied external electric field. The ice particles (to μm radius) collided with the metal target at a rate of 105 per second. The charge separation produced by different metals can be explained by the contact potential difference between the metal and the ice introducing electronic surface states on the ice. A lower limit for their density (1016m–2) is found. The influence of the electric field is explained by an interaction between Bjerrum defects and the electrons of the metal, the transfer probability depending on the charge in the surface states.

A Two-Step Process for the Formation of Au-Ge Ohmic Contacts to n-GaAs

1990 ◽  
Vol 181 ◽  
Author(s):  
M. A. Dornath-Mohr ◽  
M. W. Cole ◽  
H. S. Lee ◽  
C. S. Wrenn ◽  
D. W. Eckart ◽  
...  
Keyword(s):  
Low Temperature ◽  
Barrier Height ◽  
Gaas Substrate ◽  
Ohmic Contacts ◽  
Atomic Percent ◽  
Second Step ◽  
Semiconductor Interface ◽  
Step Process ◽  
Ohmic Behavior

ABSTRACTThe formation of low temperature Au-Ge contacts to n-GaAs is a two-step process. In the first step, the metals segregate into Au and Ge rich regions and the intermixing of the Au and Ge with the Ga and As causes a reduction in the barrier height. The second step occurs after extended annealing, during which time Au and Ge continue to diffuse into the substrate. An orthorhombic Au-Ga phase is formed and it is likely that other Au-Ga or Ge-As phases are formed. The length of the extended anneal is dependent upon the atomic percent of Ge in the film, with the 10 at. % Ge taking 6 hr., the 27 at. % Ge taking 3 hr. and the 50 at. % Ge taking 9 hr. to become ohmic. The 75 at. % Ge sample doesn’t show ohmic behavior even after 33 hr. of annealing. The metal-semiconductor interface configuration appears abrupt, showing no protrusions into the GaAs substrate.

Calculations of the Specific Resistance of Contacts to III-V Nitride Compounds

1995 ◽  
Vol 395 ◽  
Author(s):  
P.A. Barnes ◽  
X-J Zhang ◽  
M.L. Lovejoy ◽  
T.J. Drummond ◽  
H.P. Hjalmarson ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Barrier Height ◽  
Ohmic Contacts ◽  
Specific Contact Resistance ◽  
Semiconductor Interface ◽  
Barrier Heights ◽  
Effective Masses ◽  
Specific Contact ◽  
Correct Determination ◽  
Device Applications

ABSTRACTWe present calculations of the specific contact resistance for metals to GaN. Our calculations include a correct determination of the Fermi level taking into account the effect of the degenerate doping levels, required in creating tunneling ohmic contacts. Using a recently reported improved WKB approximation suitable in representing the depletion width at the metal-semiconductor interface, and a two band k-p model for the effective masses, specific contact resistance was determined as a function of doping concentration. The specific contact resistance was calculated using the best data available for barrier heights, effective masses and dielectric coefficients for GaN. Because the barrier height at the metal-semiconductor interface has a very large effect on the contact resistance and the available data is sketchy or uncertain, the effect of varying the barrier height on the calculated specific contact resistance was investigated. Further, since the III-V nitrides are being considered for high temperature device applications, the specific contact resistance was also determined as a function of temperature.

scholarly journals Charge Separation by Collision of Ice Particles on Metals: Electronic Surface States

1978 ◽  
Vol 21 (85) ◽  
pp. 547-557
Author(s):  
Othmar Buser ◽  
Claude Jaccard
Keyword(s):  
Electric Field ◽  
Charge Separation ◽  
Contact Potential Difference ◽  
Surface States ◽  
Metal Target ◽  
Contact Potential ◽  
Ice Particles ◽  
Air Speed ◽  
Electronic Surface ◽  
Transfer Probability

AbstractThe charge separation of ice particles colliding with metals was investigated in a wind tunnel (air speed 10 m/s) at a temperature of —45°C for different metals as a function of an applied external electric field. The ice particles (to μm radius) collided with the metal target at a rate of 105 per second. The charge separation produced by different metals can be explained by the contact potential difference between the metal and the ice introducing electronic surface states on the ice. A lower limit for their density (1016m–2) is found. The influence of the electric field is explained by an interaction between Bjerrum defects and the electrons of the metal, the transfer probability depending on the charge in the surface states.

scholarly journals Coupled Investigation of Contact Potential and Microstructure Evolution of Ultra-Thin AlOx for Crystalline Si Passivation

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1803
Author(s):  
Zhen Zheng ◽  
Junyang An ◽  
Ruiling Gong ◽  
Yuheng Zeng ◽  
Jichun Ye ◽  
...  
Keyword(s):  
Structural Changes ◽  
Silicon Oxide ◽  
Crystalline Silicon ◽  
Contact Potential Difference ◽  
Potential Difference ◽  
Kelvin Probe ◽  
Contact Potential ◽  
Carrier Lifetimes ◽  
Transmission Electron ◽  
Effective Carrier

In this work, we report the same trends for the contact potential difference measured by Kelvin probe force microscopy and the effective carrier lifetime on crystalline silicon (c-Si) wafers passivated by AlOx layers of different thicknesses and submitted to annealing under various conditions. The changes in contact potential difference values and in the effective carrier lifetimes of the wafers are discussed in view of structural changes of the c-Si/SiO2/AlOx interface thanks to high resolution transmission electron microscopy. Indeed, we observed the presence of a crystalline silicon oxide interfacial layer in as-deposited (200 °C) AlOx, and a phase transformation from crystalline to amorphous silicon oxide when they were annealed in vacuum at 300 °C.

scholarly journals Mechanical Properties, Corrosion Resistance and Bioactivity of Oxide Layers Formed by Isothermal Oxidation of Ti-6Al-7Nb Alloy

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 505
Author(s):  
Krzysztof Aniołek ◽  
Bożena Łosiewicz ◽  
Julian Kubisztal ◽  
Patrycja Osak ◽  
Agnieszka Stróż ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Contact Potential Difference ◽  
Isothermal Oxidation ◽  
Potential Method ◽  
Open Circuit ◽  
Kelvin Probe ◽  
Contact Potential ◽  
Oxide Layers

Titanium and its alloys are among the most promising biomaterials for medical applications. In this work, the isothermal oxidation of Ti-6Al-7Nb biomedical alloy towards improving its mechanical properties, corrosion resistance, and bioactivity has been developed. The oxide layers were formed at 600, 700, and 800 °C for 72 h. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), 3D profilometry, and microindentation test, were used to characterize microstructure, surface geometrical structure, and the hardness of the diphase (α + β) Ti-6Al-7Nb alloy after oxidation, respectively. In vitro corrosion resistance tests were carried out in a saline solution at 37 °C using the open-circuit potential method and potentiodynamic measurements. Electronic properties in the air were studied using the Scanning Kelvin Probe (SKP) technique. The bioactivity test was conducted by soaking the alkali- and heat-treated samples in simulated body fluid for 7 days. The presence of apatite was confirmed using SEM/EDS and Fourier Transform Infrared Spectroscopy (FTIR) studies. The thickness of oxide layers formed increased with the temperature growth from 0.25 to 5.48 µm. It was found that with increasing isothermal oxidation temperature, the surface roughness, hardness, corrosion resistance, and contact potential difference increased. The Ti-6Al-7Nb alloy after oxidation revealed the HAp-forming ability in a biological environment.

Sign in / Sign up

Export Citation Format

Share Document