Experimental studies of the etching of (Ba,Sr)TiO3 (BST) have been performed in Ar/halogen and Cl2 plasmas. In spite of the poor volatility of halogenated barium and strontium, some chemical enhancement of the etching reaction was observed in the etching of BST with halogen-containing plasmas. An investigation of the etching of BaOx, SrOx, TiOx, and BaxSryOz films with Cl2 plasma showed that the chemical enhancement in BST etching was related to the existence of titanium in BST films. The chemical reactivity of titanium with chlorine seemed to enhance the etching of BST. In the x-ray photoelectron spectroscopy analysis of the BST surfaces etched with Cl2 plasma, we found that barium- and strontium-rich surfaces were formed during the etching and that etching residues consisting of barium and strontium were observed after the BST films were etched off.

Ni–Fe asymmetric ring dots with partially planed outer sides were investigated as candidates for high-density magnetic memory cells. The magnetic states, which were measured with magnetic force microscopy, show that in-plane magnetic fields can control the chirality, either clockwise or counterclockwise, of vortical magnetizations of the Ni–Fe asymmetric ring dots. This control facilitates applying ring dots to the magnetic random access memories.

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Articles you may be interested inEffect of high-frequency variation on the etch characteristics of ArF photoresist and silicon nitride layers in dual frequency superimposed capacitively coupled plasmaa) Polysilicon gate etching in high density plasmas. V. Comparison between quantitative chemical analysis of photoresist and oxide masked polysilicon gates etched in HBr/Cl2/O2 plasmas J.Experimental studies of the etching of platinum have been performed with a photoresist mask in Ar/Cl 2 plasmas. The etch rate of platinum decreased with addition of Cl 2 , showing no enhancement of etching by Cl 2 addition. Moreover, the etch rate of platinum was found to be independent of substrate temperature in pure Cl 2 plasmas. These results indicated that the platinum etching with chlorine-containing plasmas is proceeded mainly by physical sputtering due to incident ions, not by chemical reactions that produce volatile etch products. Thus, in platinum etching with Ar/Cl 2 plasmas, the redeposition of nonvolatile etch products was observed to occur on sidewalls of the photoresist mask and platinum pattern; in this situation the etched profiles of platinum were tapered outwardly, because the redeposited films acted as etching masks for platinum. The thickness of deposited films on sidewalls increased with increasing Cl 2 concentration, but they were found to be removed by wet treatment with HCl solutions. It was further demonstrated that by optimizing the Cl 2 concentration, platinum could be etched without redeposition residues on sidewalls, although the etched profiles still remained outwardly tapered.