Magnetic bubble memories have been fabricated with thin‐film detectors which have a 4× improvement in signal amplitude over conventional chevron detectors. The detectors have a nominal 20‐mV signal at 25 °C when operated in a bridge configuration from a 12‐V supply. Random noise on the signal has an rms value of ∼250 μV. The temperature coefficient of the signal is approximately -1%/°C. Signal variation with drive field amplitude is ∼1% for a 1% drive field variation over a ±10% range about nominal (60‐Oe) drive. The standard conductor first structure is used, with the thin‐film detector situated between two silicon dioxide spacer layers under the conductor metalization. Nominal detector thickness is 50 nm. Relatively high detector resistance (2.5 KΩ) reduces on‐chip power dissipation to less than half that of conventional chevron detectors. Contact to the thin‐film detector is made through vias in the spacer layer. Metal‐to‐metal contact between the Al(Cu) conductor metalization and the Permalloy thin‐film detector is assured by an in‐situ sputter etch prior to Al/(Cu) deposition.
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