High performance hard magnetic NdFeB thick films for integration into Micro-Electro-Mechanical-Systems

TL;DR

This study demonstrates the successful fabrication of 5μm thick NdFeB films with high magnetic performance suitable for MEMS integration, using high rate sputtering and annealing techniques.

Contribution

It introduces a high rate sputtering process to produce thick NdFeB films with enhanced magnetic properties for micro-electromechanical systems.

Findings

Maximum remanent magnetization of 1.4 T achieved

Maximum energy product of 400 kJ/m3 comparable to sintered magnets

Films deposited at 500°C show columnar grains

Abstract

5$\mu$m thick NdFeB films have been sputtered onto 100 mm Si substrates using high rate sputtering (18 $\mu$m/h). Films were deposited at ≤ 500 C and then annealed at 750 C for 10 minutes. While films deposited at temperatures up to 450 C have equiaxed grains, the size of which decreases with increasing deposition temperature, the films deposited at 500 C have columnar grains. The out-of-plane remanent magnetization increases with deposition temperature, reaching a maximum value of 1.4 T, while the coercivity remains constant at about 1.6 T. The maximum energy product achieved (400 kJ/m3) is comparable to that of high-quality NdFeB sintered magnets.