Authors: M.T. Moneck, J.-G. Zhu
Affilation: Carnegie Mellon University, United States
Pages: 212 - 215
Keywords: methanol, reactive ion etching, ion milling, bit patterned media, spin transfer torque
Recent advances in the area of magnetoelectronics include the development of bit patterned media (BPM) for hard disk drives and the realization of spin transfer torque (STT) devices. As feature sizes shrink to sub-50 nm for STT devices and to sub-10nm for ultra-high density BPM, anisotropic, defect free etching becomes difficult with conventional techniques, such as ion milling. Instead, reactive ion etching (RIE) must be used to meet the challenge. We present research on the development of a new methanol based RIE technique for anisotropic etching of nanoscale magnetic and nonmagnetic device structures with selectivities as high as 20:1 and 90:1 respectively. Using electron beam lithography for nanoscale pattern generation, we demonstrate the ability of methanol to etch features as small as 20nm in STT and BPM related device structures with enhanced selectivity, minimal redeposition, and less faceting than similar structures etched with Ar ion milling. Furthermore, we have shown that the addition of Ar can enhance etch rate, selectivity, and directionality even further, allowing us to achieve etch rates as high as 40nm/min for alloys, such as NiFe. We will present these results, the promises of such a technique and the feasibility of etching sub-10nm dimensions.