Nanometer-sized etching of magnetic tunnel junction stack for magnetic random access memory

Abstract

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 x 200 and 100 x 100 nm(2) dimensions was successfully achieved. (C) 2006 Elsevier B.V. All rights reserved.