Abstract
A thin film microtransformer with the size of 3.14 x 3.88 mm2 was fabricated by using photolithography technology to support high-frequency switching regulators. The microtransformer was composed of sputtered amorphous magnetic layers, electroplated copper windings with 20 pm width and insulator layers. A coupling factor between the primary and secondard windings of the microtransformer was 0.97 for f= 3 MHz. The input-output voltage ratio of 0.95 at 15 MHz was obtained at no-load. The observation of the domain images under high frequency excitation indicated the magnetic anisotropy of films of the microtransformer with circular spiral coils was induced by a rotating magnetic field annealing so as to increase the output voltage.
| Original language | English |
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| Pages (from-to) | 2232-2237 |
| Number of pages | 6 |
| Journal | IEEE Transactions on Magnetics |
| Volume | 29 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 1993 Sept |