Annealing of cylindrical Ni-Fe films

Shape-induced ultrahigh magnetic anisotropy and ferromagnetic resonance frequency of micropatterned thin Permalloy films

“…As a result, a high H k ϳ 150 Oe was obtained, although both grain growth and the magnetostriction induced by SiO 2 encapsulation may have occurred. 15,18 Since high-temperature processing ͑400°C SiO 2 deposition and 350°C aluminum deposition͒ and postannealing were performed in the absence of a magnetic field, the magnetic anisotropy became aligned randomly by the local magnetization, which resulted in a constricted hysteresis loop ͓Fig. 2͑b͔͒.…”

“…However, it is well known that, for rf IC applications, Py suffers from a low magnetic anisotropy field H k ͑2-6 Oe͒, [8][9][10][11][12][13] and consequently, low FMR frequency ͑Ͻ100 MHz͒ since f r ϰ H k 1/2 . 14 More seriously, due to the growth of grains 15 and the induced magnetostriction, 16 the anisotropy field H k drops significantly at temperatures between 300-400°C. In today's stateof-the-art standard CMOS technology, there are several processing steps done at 400°C after deposition of the first aluminum metal layer.…”