IMPROVED CONTIGUOUS JUNCTION BETWEEN THE FLUX GUIDE AND TUNNEL VALVE
Original Publication Date: 2001-Dec-25
Included in the Prior Art Database: 2003-Jun-20
Abutted junction is required between the thick Flux Guide and the Tunnel Valve free layer to achieve high flux coupling efficiency. To achieve this, we disclose two approaches below: Method 1: Tunnel Valve with free layer at the top is used. The sensor cap layer is removed by etching from the passive area. then the free/pinned layers in the passive areas are oxidized to make these layers non-conducting. The Flux Guide is deposited in the passive area which makes abutted junction with the free layer. Method 2: Tunnel Valve with free layer at the top is used. The layers down to the antiferromagnet are removed from the passive area. The antiferromagnet is not removed. The junction and the top surface of the antiferromagnet are oxidized. Then the flux guide is deposited to make the abutted junction between the flux guide and the free layer. The flux guide in these structures is self-aligned with the Tunnel Valve. Same mask step is utilized to etch/oxidize the Tunnel Valve and deposit the flux guide by lift-off process.