Tunnel magnetoresistance devices processed by oxidation in air and UV assisted oxidation in oxygen

Tunnel magnetoresistance (TMR) devices were processed by sputter deposition of Co, Al and NiFe on oxidized Si wafers. After the Al deposition, an ex-s itu oxidation in air at room temperature or an in-situ oxidation enhanced b y ultraviolet (UV) irradiation in high purity oxygen at 100 mbar follows. T he electrical and magnetic properties of the junctions are measured and dis cussed concerning specific junction resistance, magnetoresistance ratio, lo ng time stability of the junctions, and failure rate of the processes. Some microscopic experiments provided consistent information of the tunnel barr ier. MR ratios between 15% and 20% were measured for the different oxidatio n processes.