Fabrication of SLM conductor-first 2 µm bubble devices

The fabrication of conductor-first, single-level-masking 2-μm magnetic bubble devices is reported. Novel features of the process, described in detail, include 1) the preparation of areas for magnetoresistive sensor in which an insulating spacer is substituted for the conductor, 2) the use of a thin layer of electrolessly deposited nickel-phosphorous on the conductor and insulator surface to minimize the coercivity of the subsequently deposited Permalloy overlay, and 3) delineation of the conductor by ion beam etching, with an Ar/O2gas mixture, using the Permalloy elements as a mask.