HIGH RESISTANCE ANODIC OXIDE FILMS ON ALUMINIUM

1966 ◽  
Vol 44 (20) ◽  
pp. 2409-2413 ◽  
Author(s):  
A. C. Harkness ◽  
L. Young
Keyword(s):  
Thin Film ◽  
Experimental Data ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Steady State ◽  
Oxide Films ◽  
Ionic Current ◽  
Anodic Oxide ◽  
Immersion Method ◽  
State Ionic

The thicknesses of oxide films formed in aqueous borate solutions were obtained by the spectrophotometric method after developing the interference colors by evaporating a very thin film of gold or bismuth onto the oxide. The refractive index of the stripped films was determined by the Becke immersion method as 1.57 to 1.58 at 5 900 Å wavelength. The dielectric constant was estimated as 9.8 ± 0.5. Experimental data on the steady state ionic current density, I, through the oxide as a function of the field strength, E, in the oxide could be represented by I = I0 exp −(W − qaE)/kT where I0 = 2.24 × 107 A cm−2, W = 1.3 ± 0.15 eV, q = 3e, a = 2.95 ± 0.15 Å.

The determination of the thickness, dielectric constant, and other properties of anodic oxide films on tantalum from the interference colours

1958 ◽  
Vol 244 (1236) ◽  
pp. 41-53 ◽  
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Oxide Films ◽  
Anodic Oxide ◽  
Effective Dielectric Constant ◽  
Immersion Method ◽  
Anodic Oxide Films ◽  
A Value ◽  
Specular Reflectivity

The thickness of anodic oxide films on chemically polished tantalum was determined from the wavelengths of the minima in the specular reflectivity using a value of the refractive index of 2·20±0·02 at 5900 Ǻ which was measured on detached flakes of the oxide by the immersion method. An auxiliary measure of increments of thickness was required for the analysis of the spectrophotometric measurements. This was provided by the quantity ( Q ∆( 1/ C )) ½ , where Q was the charge which was required to form the increment of thickness, and ∆(1/ C ) was the corresponding increase in the reciprocal capacity. This measure of thickness, like that provided by the colours, is independent of the area. The analysis gives the refractive index between 2800 and 6000 Ǻ, the net phase change in the two reflexions (with certain assumptions), and a value of ϵ/ρ, where ϵ is the effective dielectric constant under the conditions used, and ρ is the density, ρ was determined by weighing specimens in air and water. The value obtained was 7·93 ± 3%, which gives ϵ = 27·6±5%, at 1 kc/s. The effective surface area was then calculated, and was found to be very little different from the apparent area. The field strength during the formation of oxide at 9·55 mA/cm 2 and 25·8° C was found to be 6·61 x 10 6 V/cm and to be constant within experimental error, independent of thickness.

ANODIC OXIDE FILMS ON NIOBIUM: THICKNESS, DIELECTRIC CONSTANT, DISPERSION, REFLECTION MINIMA, FORMATION FIELD STRENGTH, AND SURFACE AREA

1960 ◽  
Vol 38 (7) ◽  
pp. 1141-1147 ◽  
Author(s):  
L. Young
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Field Strength ◽  
Surface Area ◽  
Current Density ◽  
Ionic Current ◽  
Anodic Oxide ◽  
Dielectric Constants ◽  
A Value ◽  
Spectrophotometric Data

The wavelengths of minimum specular reflectivity (at 11° incidence) due to interference were determined using a spectrophotometer for a series of films formed on chemically polished niobium. With a value of the refractive index n = 2.46 ± 1% at 4358 Å wavelength by the Abelès method (reported elsewhere), the spectrophotometric data give the refractive index as a function of the wavelength λ, n = 2.26 + 0.398/(λ/103 Å − 2.56)1.2. To analyze the spectrophotometric results, an auxiliary measure of thickness was required (though, with the chart given below, the thickness of a film may be determined directly from spectrophotometric measurements alone). A combination of measurements of the a-c. capacity and of the charge required to form the films gives a suitable measure of thickness (in terms of ρ/ε, where ε = dielectric constant and ρ = density) which is not dependent on a knowledge of the true surface area. The spectrophotometric data provide a calibration of this measure of thickness and thus give ε/ρ. With ρ = 4.36 g cm−3 (reported for the bulk amorphous oxide) this gives ε about 41 (compared with about 27.6 for Ta2O5). The effective surface area of the chemically polished metal was then found to be about 7% greater than the apparent area. At the ionic current density used to form the films (10 ma cm−2), the field strength in the oxide was estimated as 4.96 × 106 v cm−1 within a few per cent uncertainty. Because the field to produce a given ionic current is lower than with Ta2O5 films, the capacity of films formed to a given voltage at a given current density and temperature is not so much greater for niobium than for tantalum as the dielectric constants might lead one to expect. It is suggested that there may be a correlation between dielectric constant and ionic conductivity. The Nb2O5 films recrystallize like Ta2O5 films under an applied field but more readily, at least with the purity of metal now available.

Detection Limit of Large Area Id Thin Film Position Sensitive Detectors Based in a-Si:H P.I.N. Diodes

1995 ◽  
Vol 377 ◽  
Author(s):  
R. Martins ◽  
G. Lavareda ◽  
F. Soares ◽  
E. Fortunato
Keyword(s):  
Thin Film ◽  
Experimental Data ◽  
Steady State ◽  
Detection Limit ◽  
Large Area ◽  
Position Sensitive ◽  
Position Sensitive Detectors

ABSTRACTThe aim of this work is to provide the basis for the interpretation of the steady state lateral photoeffect observed in p-i-n a-Si:H ID Thin Film Position Sensitive Detectors (ID TFPSD). The experimental data recorded in ID TFPSD devices with different performances are compared with the predicted curves and the obtained correlation's discussed.

Determining the refractive index and the dielectric constant of PPDT2FBT thin film using spectroscopic ellipsometry

2020 ◽  
Vol 110 ◽  
pp. 110445
Author(s):  
Chandan Howlader ◽  
Mehedhi Hasan ◽  
Alex Zakhidov ◽  
Maggie Yihong Chen
Keyword(s):  
Thin Film ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Spectroscopic Ellipsometry

A STUDY FOR ANODIC OXIDE FILMS OF GaAs BY RADIOACTIVATION ANALYSIS

2001 ◽  
Vol 08 (03n04) ◽  
pp. 245-249
Author(s):  
K. YOKOTA ◽  
K. NAKAMURA ◽  
S. TAMURA ◽  
S. ISHIHARA ◽  
I. KIMURA
Keyword(s):  
Thin Film ◽  
Ethylene Glycol ◽  
Auger Electron Spectroscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Oxide Films ◽  
Anodic Oxide ◽  
Radioactivation Analysis ◽  
Anodic Oxide Films ◽  
Anodic Voltage

Gallium arsenide was anodically oxidized in a mixture of ethylene glycol and tartaric acid as an electrolyte. The numbers of Ga and As atoms in the anodic oxide films and in the used electrolytes were measured by radioactivation analysis. During the anodic oxidation, GaAs dissolved into the electrolyte. The numbers of Ga and As atoms that dissolved into the electrolytes was proportional to the anodic voltage, and the number of Ga atoms in the electrolyte was about five times more than that of As atoms. The composition of the anodic oxide films varied with depth. However, the atomic profiles measured by Auger electron spectroscopy displayed As atoms much less than Ga atoms throughout the anodic oxide films, because Ga oxides were lost from the anodic oxide films into the vacuum during the Auger electron spectroscopy, accompanying sputtered thin film removal.

KINETICS OF FORMATION OF ANODIC OXIDE FILMS ON BISMUTH

1962 ◽  
Vol 40 (5) ◽  
pp. 903-920 ◽  
Author(s):  
L. Masing ◽  
L. Young
Keyword(s):  
Steady State ◽  
Oxide Films ◽  
Transient Behavior ◽  
Anodic Oxide ◽  
Transient Kinetics ◽  
Crystal Face ◽  
Anodic Oxide Films ◽  
Kinetics Of Formation ◽  
Kinetics Of ◽  
Better Than

The steady-state and transient kinetics of formation of thin insulating anodic oxide films on bismuth have been investigated. The thickness of the films was determined by the spectrophotometric method. No dependence on the crystal face of the substrate was detected (sensitivity better than 1% with thicker films). The transient behavior was found to be somewhat different from that of tantalum. The activation distances were found to be unusually large. The dielectric properties were also investigated.

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