Aluminum oxide film prepared by plasma enhanced chemical vapor deposition (PECVD) is one of the promising candidates for an etch mask or an etch barrier material in very large scale integrated fabrication. We have investigated the reactive ion etching mechanism of the PECVD aluminum oxide films in the CF4/O2 plasma. The dependences of the aluminum oxide etch rate on the atomic fluorine concentration and the incident particle bombardment energy are studied at various etching conditions. The etch products and their depth distribution are also determined by analyzing the surface layer of the etched aluminum oxide films with Auger electron spectroscopy. The CF4/O2 plasma fluorinates the aluminum oxide surface layer through the particle bombardment activated reaction, producing etch products in the form of AlF3 or AlOXFY, which is nonvolatile but has a higher sputtering yield than aluminum oxide. The reactive ion etching of aluminum oxide proceeds by the formation and the sputter removal of the etch product. The etch rate strongly depends on the particle bombardment energy because it determines not only the formation rate but also the removal rate of the etch products. However, the atomic fluorine concentration has little effect on the etch rate because the consumption rate of fluorine radicals is so low that they are always superfluous under any experimental conditions.

This article presents the characteristics of the enhanced isolation antenna realized for EGSM/DCS systems.The proposed antenna consists of the two radiation planar inverted F antennas are orthogonally arranged. The operating frequency of the two radiators is designed to be equal and enhanced isolation of −18 ∼ −21 dB is achieved. A high isolation is obtained by adding additional ground path of the antenna. The multiple‐input multiple‐output structure gives high gain and low correlation (< 0.2). Details of the proposed antenna are described and experimental results of constructed prototype also are presented. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:802–805, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26637

This paper presents the characteristics of the miniaturized Z‐shaped meander‐type antenna realized for 5.25‐GHz wireless LAN systems. The proposed antenna consists of the modified meander line, corrugated shape, and shorting pin with coaxial feeding on the two‐layered (air and FR4) substrate, which forms the letter “Z.” This proposed antenna has equivalent performance with about 44.87% of size reduction with respect to conventional antennas. Its maximum measured impedance bandwidth (−10‐dB below) is approximately 300 MHz (5.05–5.35 GHz) or 5.76%, which meets to the bandwidth requirement of WLAN (5.15–5.35 GHz) systems. Details of the proposed antenna are described and experimental results of constructed prototypes also are presented. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1269–1271, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21673