Low Temperature Intermixing Reactions Between Silicon and Metals

1981 ◽  
Vol 10 ◽  
Author(s):  
Akio Hiraki ◽  
T. Narusawa ◽  
W. M. Gibson
Keyword(s):  
Film Thickness ◽  
Metal Film ◽  
Dielectric Constants ◽  
Semiconductor Surface ◽  
Free Electrons ◽  
Coulombic Interaction ◽  
Screening Model ◽  
Energy Gaps ◽  
Deposited Metal ◽  
Critical Film Thickness

Metal films such as gold, copper, nickel and palladium exhibit an interfacial intermixing reaction at room temperature with semiconductors with energy gaps Eg less than about 2.5 eV or dielectric constants ε larger than about 81. We have proposed a model2 of the triggering mechanism of this interfacial reaction based on the ability of a metal to screen coulombic interaction by its mobile free electrons. Such a screening may disturb the electron distribution responsible for the covalent bonding, and consequently it may make the semiconductor surface reactive towards the metal. In this respect, there must be a critical film thickness for the deposited metal film to behave as a true metal with sufficient mobile free electrons for the screening; therefore the reactivity of the semiconductor surface for the intermixing reaction must be dependent on the thickness of the deposited metal film. In favour of the screening model, we show that the reactivity of a silicon surface for intermixing or silicide formation with a gold or palladium film depends clearly on the film thickness.

Tunnelspektroskopie an dünnsten supraleitenden Aluminium-, Indium- und Bleischichten / Superconducting Tunneling into Ultrathin Aluminum, Indium and Lead Films

1974 ◽  
Vol 29 (2) ◽  
pp. 319-331
Author(s):  
H. Sixl ◽  
J. Gromer ◽  
H. C. Wolf
Keyword(s):  
Film Thickness ◽  
Electronic States ◽  
Silicon Monoxide ◽  
Quantum Size ◽  
Energy Gaps ◽  
Electron Phonon Coupling ◽  
Critical Film Thickness ◽  
Lead Films ◽  
Bias Range ◽  
Marked Dependence

We report about tunneling experiments on extremely thin superconductors with barriers of aluminium- oxide and in addition silicon-monoxide or naphthalene, all condensed at 4.2 °K. The tunneling spectra of aluminium, indium and lead films show a large tunneling anomaly at a film thickness just above the critical thickness for conductivity and superconductivity: in the low bias range (between 2 and 5 mV) the tunneling resistivity dU/dI is increased by about 20 to 30 per cent with respect to the corresponding resistance of thicker films. This anomaly disappears when the film thickness is increased by 30 to 40 Å. Two models are presented, which can explain the tunneling anomaly by the quantum size effect in the very thinnest films of either the phonon states or the electronic states. The energy gaps and the transition temperatures of the superconductors show a marked dependence on the film thickness between the critical film thickness and 300 Å, dependent on both, the superconductor itself and on the substrate, naphthalene or silicon-monoxide. This dependence can be described completely by the altered electron-phonon coupling at the film surfaces and by size quantization of the electronic states.

The method of replication affects metal film granularity and resolution

1989 ◽  
Vol 47 ◽  
pp. 708-709
Author(s):  
George C. Ruben
Keyword(s):  
Electron Beam ◽  
High Resolution ◽  
Film Thickness ◽  
Single Molecule ◽  
Metal Film ◽  
Vertical Surface ◽  
High Resolution Imaging ◽  
Controllable Factors ◽  
Resolution Imaging

Single molecule resolution in electron beam sensitive, uncoated, noncrystalline materials has been impossible except in thin Pt-C replicas ≤ 150Å) which are resistant to the electron beam destruction. Previously the granularity of metal film replicas limited their resolution to ≥ 20Å. This paper demonstrates that Pt-C film granularity and resolution are a function of the method of replication and other controllable factors. Low angle 20° rotary , 45° unidirectional and vertical 9.7±1 Å Pt-C films deposited on mica under the same conditions were compared in Fig. 1. Vertical replication had a 5A granularity (Fig. 1c), the highest resolution (table), and coated the whole surface. 45° replication had a 9Å granulartiy (Fig. 1b), a slightly poorer resolution (table) and did not coat the whole surface. 20° rotary replication was unsuitable for high resolution imaging with 20-25Å granularity (Fig. 1a) and resolution 2-3 times poorer (table). Resolution is defined here as the greatest distance for which the metal coat on two opposing faces just grow together, that is, two times the apparent film thickness on a single vertical surface.

Evaluation of thin metal film thickness from light attenuation and multi-reflection effects on micro-Raman response

2013 ◽  
Vol 536 ◽  
pp. 142-146 ◽  
Author(s):  
C. Camerlingo ◽  
M.P. Lisitskiy ◽  
L. De Stefano ◽  
I. Rea ◽  
I. Delfino ◽  
...  
Keyword(s):  
Film Thickness ◽  
Metal Film ◽  
Light Attenuation ◽  
Thin Metal Film ◽  
Thin Metal ◽  
Raman Response

scholarly journals Strong Coupling of Folded Phonons with Plasmons in 6H-SiC Micro/Nanocrystals

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2296 ◽  
Author(s):  
Yao Huang ◽  
Run Yang ◽  
Shijie Xiong ◽  
Jian Chen ◽  
Xinglong Wu
Keyword(s):  
Silicon Carbide ◽  
Electrical Properties ◽  
Raman Scattering ◽  
Film Thickness ◽  
Strong Coupling ◽  
Energy Gaps ◽  
Longitudinal Optic ◽  
Transverse Optic

Silicon carbide (SiC) has a large number of polytypes of which 3C-, 4H-, 6H-SiC are most common. Since different polytypes have different energy gaps and electrical properties, it is important to identify and characterize various SiC polytypes. Here, Raman scattering is performed on 6H-SiC micro/nanocrystal (MNC) films to investigate all four folded transverse optic (TO) and longitudinal optic (LO) modes. With increasing film thickness, the four folded TO modes exhibit the same frequency downshift, whereas the four folded LO modes show a gradually-reduced downshift. For the same film thickness, all the folded modes show larger frequency downshifts with decreasing MNC size. Based on plasmons on MNCs, these folded modes can be attributed to strong coupling of the folded phonons with plasmons which show different strengths for the different folded modes while changing the film thickness and MNC size. This work provides a useful technique to identify SiC polytypes from Raman scattering.

scholarly journals Влияние напряжения смещения и скорости осаждения на структуру и коэрцитивность пленок NiFe

2020 ◽  
Vol 62 (12) ◽  
pp. 2174
Author(s):  
А.С. Джумалиев ◽  
C.Л. Высоцкий ◽  
В.К. Сахаров
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Film Thickness ◽  
Deposition Rate ◽  
Entire Range ◽  
Soft Magnetic Properties ◽  
Supercritical State ◽  
Dc Magnetron Sputtering ◽  
Soft Magnetic ◽  
Critical Film Thickness

Influence of the bias voltage Ub and the deposition rate  on the structure, grain size D, and coercivity Hc of NiFe films with the thickness d from 30 to 980 nm, grown onto Si / SiO2 substrates by DC magnetron sputtering, was studied. In the case Ub = 0, the decrease of  from ≈ nm/min to ≈ 7 nm/min is accompanied by the increase of the critical film thickness dcr from dcr ≈ 220 nm to dcr ≈ 270 nm. In this case, Hc in the films with d < dcr is characterized by the dependence Hc ~ D6 and varies from ~ 1 to ~ 20 Oe. In the case of Ub = -100 V, the effect of the deposition rate on the coercivity is much more noticeable. At ν = 7 and 14 nm / min, the films demonstrate soft magnetic properties (Нс ≈ 0.15 - 1.4 Oe) and the absence of dcr for the entire range of studied thicknesses. The films obtained at ν = 21 and 27 nm / min turn into the “supercritical” state at d ≥ dcr ≈ 520 nm, and, in the region d < dcr, they are characterized by the dependence Hc ~ D3 and by the increase of coercivity from ~ 0.35 to ~ 10 Oe.

scholarly journals Solar Cells Efficiency Increase Using Thin Metal Island Films

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Alexander Axelevitch ◽  
Gady Golan
Keyword(s):  
Solar Cells ◽  
Light Exposure ◽  
Resonant Absorption ◽  
Modern Technology ◽  
Semiconductor Surface ◽  
Free Electrons ◽  
Efficiency Increase ◽  
Metal Island ◽  
Rough Calculation ◽  
Metal Islands

Metal nanodimension structures have multiple applications in modern technology. Noncontinuous thin island metal films of several types of metals deposited on dielectric or semiconductor surface introduce a unique behavior. In response to light exposure in certain range, the metal islands present a resonant absorption of light accompanied with a collective behavior of free electrons in these islands. In this paper, we present one of the possible ways to increase the efficiency of solar cells with metal islands imbedded in a semiconductor junction. Rough calculation was performed for a silicon solar cell and showed an increase of 17.5% in the overall efficiency of the cell.

Electronic eigenvalues of copper

1953 ◽  
Vol 220 (1143) ◽  
pp. 513-529 ◽  
Keyword(s):  
Brillouin Zone ◽  
Metallic Copper ◽  
Copper Ion ◽  
Wave Functions ◽  
Free Electrons ◽  
Cubic Crystal ◽  
Conduction Electrons ◽  
Energy Gaps ◽  
The Face ◽  
Cellular Method

The cellular method as developed by Howarth & Jones (1952) is applied to the face-centred cubic crystal, and, in particular, the eigenvalues and wave functions of the 3 d and 4 s electrons in metallic copper are obtained for states whose wave vectors lie at the ends of the three- and four-fold axes in the Brillouin zone. The conduction electrons approximate closely to free electrons inside the first Brillouin zone, but the energy gaps at the zone faces are found to be sensitively dependent upon the potential used to represent the copper ion. The eigenvalues of the 3 d band agree closely with Fletcher’s results for nickel, and show a band width of 3·46 eV. An approximate solution of the Hartree equations for the metal shows the top of the d -band to lie 3·7 eV below the Fermi level in the conduction band.

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