The application of the barrier-type anodic oxidation method to thickness testing of aluminum films

Abstract

The thickness of the active metal oxide film formed from a barrier-type anodizing process is directly proportional to its formation voltage. The thickness of the consumed portion of the metal film is also corresponding to the formation voltage. This principle can be applied to the thickness test of the metal films. If the metal film is growing on a dielectric substrate, when the metal film is exhausted in an anodizing process, because of the high electrical resistance of the formed oxide film, a sudden increase of the recorded voltage during the anodizing process would occur. Then, the thickness of the metal film can be determined from this voltage. As an example, aluminum films are tested and discussed in this work. This method is quite simple and is easy to perform with high precision.

Minimizing Visceral Fat Delocalization on Tissue Sections with Porous Aluminum Oxide Slides for Imaging Mass Spectrometry

“…After 10 min of anodization, small holes were formed, and major structural changes were observed after 20 min. On the other hand, barrier type aluminum oxide slides were formed in diluted tartaric acid, which does not dissolve aluminum oxide . After the surface is completely passivated (after 4 min according to Chen et al), the surface topography does not change.…”

“…The end not covered in parafilm was then attached to an alligator clip connected to the positive terminal of a potentiostat. The slides were then oxidized following one of two protocols to obtain either a barrier type (BAR) oxide layer or a porous type (POR) oxide layer. , To obtain a porous type aluminum oxide, the slides were plunged in a 15% sulfuric acid solution with a potential of 8 V. Four different anodization times were analyzed (10, 20, 30, and 40 min). Solutions may become slightly pink while undergoing oxidization due to possible manganese contaminant present in 6061-T6 grade aluminum .…”

“…42 To obtain a barrier type aluminum oxide slide, the slides were plunged into 3% tartaric acid (Sigma) solution at pH 5.5 for 10 min at four different potentials ( V). As explained by Chen et al, 40 to obtain a barrier type oxide, pH should be adjusted to pH 5.5 with ammonia to ensure that no ions in solution can solubilize aluminum oxide. 40 In all cases, an aluminum rod was used as a counter electrode (12 × 0.8 × 1.8 cm).…”

Ionic transport and barrier effect of anodic oxide layer in a solid-state Al2O3 capacitor under high electric field

“…The structural and absorbed water of the hydrated AmAO film, which acts as an effective solid state electrolyte, is supposed to be the supplier of O 2and/or OHfor anodic oxidation [18,19]. The reactions at the anode and cathode might be described as follows: According to the theory of barrier-type anodic oxide film growth [24,38], the thickness of the newly-formed oxide layer depends on the positive voltage applied to the Al electrode pad. It has been found that the thickness of the newly-formed aluminum oxide film increased linearly with the positive voltage at a slope of 0.456±0.001 nm/V [13].…”

“…The distance between the centers of the electrode pads was 2 mm. The thickness of the Al films was about 100 nm measured by an anodizing method using 3% ammonium tartrate aqueous solution as electrolyte [24]. Before electrical measurement, the AmAO films were hydrated at room temperature under relative humidity of 50% for 60 min in a GP/TH-50 humidity chamber (Guangpin, China).…”