Search

Inductively coupled plasma reactive ion etching of CoFeSiB magnetic thin films was studied in a Cl2/O2/Ar gas mix. The etch rate, etch selectivity and etch profile of this magnetic film were examined on varying gas concentration, coil rf power, gas pressure and dc-bias voltage. As the Cl2 gas increased, the etch rate monotonously decreased and etch residues decreased but etch slope was slanted. The use of the TiN hard mask gave rise to high selectivity of CoFeSiB to the TiN mask due to large decrease in etch rate of TiN in Cl2/O2/Ar gas mix. The addition of O2 into the gas mix led to the anisotropic etching of CoFeSiB films without the etch residues.

In this study, a novel method is being proposed for the formation of nanostructures, utilizing the electrochemical anodization of Al/metal layers and high density plasma etching. Self-assembled metal oxide pillars formed by anodizing Al/metal layers were employed as an etching mask for nanostructure formation. Once the shape and size of the metal oxide pillars have been determined, the shape and size of the Si dots are dependent on the etching conditions such as etching gas, coil power, and dc-bias. The etch characteristics of Si film and metal oxide pillars were investigated with regard to etch rate, selectivity and profile. Highly ordered Si nanodot arrays were fabricated on a wafer using optimized etching conditions.

Inductively coupled plasma reactive ion etching of GeSbTe (GST) thin films with a photoresist mask was carried out in a Cl2/Ar gas. The monotonous increase in etch rate with increasing Cl2 concentration indicates that the etching of GST films obeys the reactive ion etching mechanism. The etch rates increased with increasing coil rf power and dc-bias voltage. The etch profiles was improved with decreasing coil rf power and dc-bias voltage and gas pressure gave little influence on the etch profile. The x-ray photoelectron spectroscopy analysis reveals that the rate limiting step in GST etching study is the etching of Te. Anisotropic etching of GST films was achieved using a Cl2/Ar chemistry at the optimized etch conditions.

Inductively coupled plasma reactive ion etching of CoZrNb magnetic thin films was studied using a TiN hard mask in a Cl2/O2/Ar gas mix. The etch rates of CoZrNb films and TiN hard mask gradually decreased with increasing Cl2 or O2 gas concentrations. When O2 gas was added in the Cl2/Ar gas mix, the etch rate of TiN hard mask was suppressed effectively so that the etch selectivity of CoZrNb film to TiN hard mask was enhanced. The addition of O2 into the gas mix also led to the anisotropic etching of the CoZrNb films and it was confirmed by Auger electron spectroscopy that there were no redeposited materials on the sidewall of the etched films. Highly anisotropic etching of CoZrNb films was achieved at room temperature under the optimized etching conditions.

High-density plasma reactive ion etching of MTJ stack was investigated in an inductively coupled plasma of Cl 2 /Ar and Cl 2 /O 2 /Ar gas mixes. Thin TiN hard mask was employed and the etching proceeded at ambient temperature. The effect of etch gas on the etch profiles of MTJ stack was examined by varying the gas concentration. In addition, the effects of etch parameters on the etch profiles and magnetic properties of MTJ stacks were investigated. The highly anisotropic etching of MTJ stack arrays with 200×200 and 100×100 nm 2 dimensions was successfully achieved.

The fabrication of nanostructures using self-organized niobium oxide nanopillars was investigated by high-density plasma reactive ion etching in a Cl2/Ar gas. Etch rates and etch profiles of niobium oxide pillars were examined by varying etch parameters. We confirmed that several nanostructures, such as nanotip and nanodot arrays, could be fabricated over large areas using optimal anodizing and etching conditions. The mechanism of forming different nanostructures were classified into two groups, isotropic and anisotropic etch mechanisms. It is expected that a novel technique proposed in this study offers a simple and cost-effective method for fabricating nanostructures from various material systems. © 2005 The Electrochemical Society. DOI: 10.1149/1.1990027 All rights reserved.