Thin film techniques for fabricating narrow track ferrite heads

A process for producing a reactive ion etched structure with height and width dimensions of the order of 25 microns or less on a ferrite substrate surface comprising the steps of

• depositing an electrically conductive layer on the substrate surface,
• forming a mask of positive photoresist on said conductive layer,
• plating said conductive layer exposed by said mask with one of the group consisting of nickel and nickel-iron alloys,
• removing said photoresist mask to leave a pattern of said plated metal,
• reactive-ion etching the ferrite substrate surface that is exposed by said pattern with a power of >1 watts/cm.sup.2 of cathode area and a bias voltage <-100 volts, and
• removing said metal pattern to leave said etched structure.