Device geometry effects in an integrated power microinductor with a Ni ₄₅Fe₅₅ enhancement layer

In an integrated power microinductor, the size and shape of the magnetic material will have a relationship to the permeability and inductance of the device. To demonstrate these effects, a set of inductors with closed Ni ₄₅Fe₅₅ films were fabricated having similar structures but different footprint sizes and aspect ratios (ARs). Magnetic and electrical characterization was performed on the devices to determine magnetic properties, and in both measurements the same relationship between film shape and magnetic anisotropy is observed. Micromagnetic shape anisotropy simulations were used to predict this behavior and correlate with the experimentally determined parameters. The AR of the film is determined to have a strong influence on the anisotropy and permeability of the magnetic film via shape demagnetization effects which is shown to be a significant variation from the as-deposited magnetic material parameters.