Nd–Fe–B Film Magnets With Thickness Above 100 ${\mu }\text{m}$ Deposited on Si Substrates

Abstract

We have already reported the isotropic Nd-Fe-B thick-films with the thickness range from 10 to 1200 μm by using a PLD (Pulsed Laser Deposition) method and applied them to several electronic devices [1,2]. The thick-films were deposited on various metal substrates such as a Ta and a Fe ones. On the other hand, several researchers demonstrated the deposition of Nd-Fe-B thick-films with a buffer layer on Si substrates using a sputtering method to develop MEMS by taking account of micromachining technology [3], and the thickness of each film was mainly less than 20 μm. Although we also tried to prepare isotropic Nd-Fe-B thick-films on Si substrates with a Ta buffer layer [4], the samples were broken after a dicing process due to the mechanical property of Ta. This contribution reports a control of microstructure of samples enables us to increase the thickness above 100 μm without a buffer layer on a Si substrate. Namely, we found that the precipitation of Nd at the boundary of Nd-Fe-B grains is effective to suppress the destruction of samples through an annealing process. Resultantly, we could increase the thickness of Nd-Fe-B films up to approximately 160 μm deposited on Si substrates. The magnetic properties of the samples were comparable to those of previously reported ones deposited on metal substrates. Furthermore, no deterioration of mechanical and magnetic properties could be achieved after a dicing process.