Corona Discharge Technique Research Articles

Poling of Lead Zirconate Titanate Ceramics and Flexible Piezoelectric Composites by the Corona Discharge Technique

In the conventional poling method, piezoelectric ceramics and composites are poled by applying a large dc voltage. Poling of composites having a polymer matrix with 0–3 connectivity is especially difficult because the electric field within the high‐dielectricconstant grains is far smaller than in the low‐dielectric‐constant polymer matrix. Therefore, very large electric fields are required to pole these types of composites. However, large electric fields often cause dielectric breakdown of the samples. In this study for improved poling, the corona discharge technique was used to pole piezoelectric ceramics, fired PZT composites, and 0.5PbTiO3· 0.5BiFeO3 0–3 polymer composites. An experimental setup for corona poling is described. The dielectric and piezoelectric properties of materials poled by the corona discharge technique were comparable to those obtained with the conventional poling method.

Conformal Two‐Dimensional SiO2 Layers on Silicon Grown by Low Temperature Corona Discharge

A low temperature oxygen corona discharge technique, previously used to relax the stresses developed in planar oxides, has been used to grow films on two‐dimensional structures at temperatures ≤900°C in dry . The resulting oxide films are found to be much more conformal (uniform) around both convex and concave surfaces than those found for thermally grown oxides. It is postulated that the corona oxidation relaxes oxide network strains which reduce the interface reaction rate constant for both convex and concave cases and which block diffusion of oxidant in the concave case.

Stress relaxation technique for thermally grown SiO2

A corona discharge technique has been utilized at 800 °C to fully relax thermal oxides grown on Si wafers. In an experiment involving two oxidation steps, the corona-relaxed oxides are shown to be equivalent to ∼1200 °C thermally grown or thermally relaxed oxides, both with respect to index of refraction and oxygen diffusion coefficient. The activation energy for oxygen diffusion through a completely relaxed thermal oxide is found to be 0.8 eV.