Simulation of Ion Beam Etching of Patterned Nanometer-scale Magnetic Structures for High-Density Storage Applications

Introduction

Fabrication of various nano-structures often requires mask controlled or patterned etching of materials. The chemical or wet etch methods cannot be used for nanoscale geometries due to the substantial isotropic component of etch rate. Therefore, various plasma or reactive ion etching method are typically used. Unfortunately, some materials do not easily form volatile reaction products and all types of chemically assist etching becomes problematic. Among those materials are elements such as Co, Ni, Fe, Pt, and Cr which are usually used in magnetic nano-structure technologies. Therefore, ion beam etching or ion milling is the most suitable method to pattern these materials [1].

The most promising magnetic nano-technology application is the Bit Pattern Media (BPM). The BPM technology has a potential to manufacture Hard Drive Discs (HDD) with density of up to few terabytes per square inch. To achieve such high density, huge arrays of single domain magnetic islands of ~10 nm diameter must be formed. Other essential requirements for manufacturing of high-density BPM are as small as possible distance between these magnetic islands and as vertical as possible sidewalls of the islands.