Air Gap Material Research Articles

Growth behavior and substrate selective deposition of polypyrrole, polythiophene, and polyaniline by oxidative chemical vapor deposition and molecular layer deposition

Bottom-up self-aligned area-selective deposition (ASD) plays an important role in patterning of advanced electronic devices. Specifically, ASD of organic materials can be utilized for nucleation inhibitors, sacrificial layers, and air-gap materials for next-generation nanoscale processing. This work introduces fundamental growth behavior of various conjugated polymers including polypyrrole, polythiophene, and polyaniline via oxidative molecular layer deposition and chemical vapor deposition. Effects of process parameters on film properties are described, and ASD behavior of different polymers are quantitatively characterized. These findings expand fundamental understanding of conjugated polymer deposition and provide new perspectives for ASD of organic thin films.

Nanopatterned Area-Selective Vapor Deposition of PEDOT on SiO2 vs Si-H: Improved Selectivity Using Chemical Vapor Deposition vs Molecular Layer Deposition

Area-selective deposition (ASD) of polymers is expected to be useful for self-aligned patterning of nucleation inhibitors, sacrificial layers, and air-gap materials during future bottom-up nanoscal...

Vibration and acoustic noise of industrial inductors associated to converters in the railway domain

Purpose The purpose of this paper is to present an original study of industrial inductors with different air-gap materials in order to reduce the vibration and noise of inductors. Acoustic comfort is an increasingly important factor at the design stage of industrial inductors associated to converters. In addition, power converters in the railway domain are more and more compact and powerful. Design/methodology/approach Experiments, simulations and test devices were used to determine the main physical phenomena that generate the undesirable audible noise. Electric and vibratory measurements (modal and operational analysis) were compared with the numerical calculations. PWM and sinusoidal supply were taken into account and different prototypes with different materials in the air-gap were built. Findings This study analyzes and details the origin of the electromagnetic noise due to the vertical mode, in order to reduce the vibration and noise of inductors. A detailed analysis using finite element simulation and experimental measurements of free-free mode or forced mode under electrical excitation was conducted to interpret the vibrations of the structure. In addition, in order to observe trends and the impact of magnetostriction effect, the authors propose a simplified model. Practical implications Electric and vibratory measurements (modal and operational analysis) are compared with the numerical calculations. Originality/value This paper gives a response about the origin of the noise with different experimental measurements. Changing the air-gap material is beneficial for the deflection of the inductor. However, it has been presented that, following the shape of the inductor, it is beneficial to reduce or increase the stiffness of the material depending on the column height. For a fixed Young’s modulus air-gap, a ratio Column height/air-gap thickness exists, which makes it possible to cancel the deflection.

Comparison of Realization Techniques for PFC Inductor Operating in Discontinuous Conduction Mode

Several design techniques are compared for producing a power factor correction (PFC) boost inductor operating in discontinuous conduction mode. In this application, fringing fields associated with high frequency current pulses cause problems of winding loss in the vicinity of an air gap, in particular with planar core shapes. For this reason, a planar inductor in which a lumped gap is replaced by a distributed air gap material is described and investigated. The consequences of lumped versus distributed air gap for the losses of the boost inductor are investigated. A significant reduction in AC winding loss of the planar structure with the composite core is demonstrated. However, the trade-off between reduced winding loss and increased core loss for this technique has to be considered along with the selection of proper winding technology. Four boost inductor design realizations are built and compared. Presented winding loss models are verified with measurements on prototypes operating in an 80 W PFC converter.

Optimization of CVD dielectric process to achieve reliable ultra low- k air gaps

The capability of CVD silicon oxide has been studied to achieve a controlled air gap between copper interconnects for sub-quarter micron CMOS technologies. Several deposition parameters have been investigated and their influence on air gap morphology and electrical performances are shown in this paper. A reliable process has been obtained from these experiments. The parasitic capacitance between lines is reduced by half using SiO 2 air gap material.