Ion implantation method for fabricating magnetoresistive (MR) sensor element

A method for forming a magnetoresistive (MR) sensor element having a magnetoresistive region of final dimensions comprising:

• providing a substrate;
• forming over the substrate an initial magnetoresistive (MR) layer having initial dimensions;
• forming over said initial magnetoresistive (MR) layer an ion-implantation mask which is resistant to transmitting ions, the dimensions of said mask being the final dimensions of said magnetoresistive region;
• implanting said initial magnetoresistive (MR) layer with ions of a particular species such that said ions penetrate the portion of said initial magnetoresistive (MR) layer not protected by said ion-implantation mask with sufficient energy and dosage to destroy the magnetoresistive properties of said portion while retaining its structural and electrical properties;
• and
• forming, thereby, a layer having said initial dimensions, which comprises a magnetoresistive region of said final dimensions and a contiguous ion-implanted region having no magnetoresistive properties, but upon which contiguous region subsequent material layers can be formed and to which contiguous region electrical connections can be made by said material layers;
• and
• forming a patterned electrical lead layer over each of the ion-implanted regions of the magnetoresistive (MR) layer, said lead layers being in electrical contact with each of the said ion-implanted regions.