Junctions between Permalloy and ion-implanted tracks for high-density hybrid bubble memory devices (>or=16 Mb/cm2) using 0.5- mu m-diameter bubbles have been investigated at a 100-kHz drive field. The conventional junctions developed for 4-Mb/cm2 devices have been found not to work at all. A novel type of asymmetric chevron (AC) junction has been proposed and operated. With the large volume of AC Permalloy patterns and the shallow ion-implanted channel, AC junctions show an operating bias-field margin of more than 6%. The feasibility of junctions for hybrid devices with 16-Mb/cm2 storage density has been confirmed.