Electromagnetic device having layered magnetic material components and methods for making same
A micro fabricated electromagnetic device and method for fabricating its component structures, the device having a layered magnetic core of a potentially unlimited number of alternating insulating and magnetic layers depending upon application, physical property and performance characteristic requirements for the device. Methods for fabricating the high performing device permit cost effective, high production rates of the device and its component structures without any degradation in device performance resulting from component layering.
1. A micro multilayered electromagnetic device, comprising:
a coil;
a continuous closed loop laminated magnetic core, the magnetic core including a silicon microbeam,
a dielectric substrate or seed layer operatively connected to and covering the microbeam, and
a multilayered magnetic structure operatively connected the microbeam the multilayered magnetic structure including;
a first layer of magnetic micro laminate material, the first layer including a magnetic cobalt-nickel-iron alloy layer operatively connected to the substrate or seed layer and a layer of iron oxide insulating material operatively connected to the magnetic cobalt-nickel-iron alloy layer, a plurality of layers of micro laminate material sequentially deposited on and operatively connected to the first layer of magnetic micro laminate, material and to one another, and
a cobalt layer having a preselected thickness disposed intermediate every fifth to every tenth of the plurality of micro laminate material layers, whereby an inhibiting effect of a passivating oxide layer of the nickel component of the alloy to the formation of an insulating layer of iron oxide thereon is overcome.
2. The micro multilayered electromagnetic device of claim 1 wherein the iron oxide comprises hematite (Fe 2 O 3 ) or magnetite (Fe 3 O 4 ).
3. The micro multilayered electromagnetic device of claim 2 wherein each layer of insulating material is of a preselected thickness in the range of 0.05 μm to 0.5 μm.
4. The micro multilayered electromagnetic device of claim 3 wherein the thickness of the cobalt layer is 0.5 μm or less.
5. The micro multilayered electromagnetic device of claim 1 wherein the alloy layer comprises cobalt in a range of 25% to 45%, nickel in a range of 45% to 65%, and iron in a range of 1% to 18%.
6. The micro multilayered electromagnetic device of claim 5 wherein the magnetic laminate core has a thickness of 250 μm.