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[Al.sub.2][O.sub.3] films made with atomic layer deposition (ALD) have been developed for use as isolation layers in CPP tunneling magnetoresistive readers. A low-temperature deposition process was developed to permit integration with a self-aligned patterning scheme. The resulting films show excellent thickness uniformity (< 2% within-wafer), leakage current density ([J.sub.leak] < 1 x [10.sup.-8] A][cm.sup.2]) and breakdown properties ([F.sub.bd] > 9 MV/cm). TEMs of sub-100 nm TMR readers fabricated using these processes show > 95% conformality on junction sidewalls, indicating nonselective growth of ALD [Al.sub.2][O.sub.3] on the various stack and bottom shield surfaces. Permanent magnets with well-controlled junction grain structure and coercivities in excess of 2500 Oe have been deposited with existing processes. FEM modeling shows the effective stabilizing field from the magnets at the junction edge scales inversely with ALD layer thickness, in agreement with device-level free layer stability metrics showing improvements at lower ALD thicknesses. As the conformal ALD layer thickness is easily tuned, this technology provides flexibility in trading off reader amplitude and stability that should support scaling of the abutted TMR design out to 1 Tb/[in.sub.2] and beyond. Index Terms--Atomic layer deposition, isolation, permanent magnet, reader, tunneling magnetoresistance.

Microstructural investigations of CoCrPt/Cr and CoCrPt/CrV magnetic thin film media were conducted in order to explain improved media performance as a function of increased Cr concentration in the magnetic layer and a pre-deposition treatment of the NiP plated Al substrate. Using High Resolution Transmission Electron Microscopy (HRTEM) and Selected Area Diffraction Patterns (SADP) it was found that for both underlayer structures, no significant microstructural differences (such as grain size, stacking fault density, orientation, crystalline phase, and bi-crystals) exist between samples grown with 13% Cr and 22% Cr. This indicates that Cr segregation to grain boundaries is the most likely mechanism for improved S/N ratio and higher coercivity. The increased coercivity observed in the treated samples is consistent with an increased grain size in the magnetic layer due to larger Cr underlayer grains.

Magnetic force microscopy is used for imaging the domains in thin nanocrystalline CoCrPt films that are part of a patterned read sensor device. The change in net magnetization has occurred in discrete local moment switching similar to Barkhausen jumps, where moments of weakly coupled grains have irreversibly rotated at fields that are lower than the bulk coercive field of the film.

Al2O3 films made with atomic layer deposition (ALD) have been developed for use as isolation layers in CPP tunneling magnetoresistive readers. A low-temperature deposition process was developed to permit integration with a self-aligned patterning scheme. The resulting films show excellent thickness uniformity (<2% within-wafer), leakage current density (Jleak < 1 x 10-8 A/cm²) and breakdown properties (Fbd > 9 MV/cm). TEMs of sub-100 nm TMR readers fabricated using these processes show > 95% conformality on junction sidewalls, indicating nonselective growth of ALD Al2O3 on the various stack and bottom shield surfaces. Permanent magnets with well-controlled junction grain structure and coercivities in excess of 2500 Oe have been deposited with existing processes. FEM modeling shows the effective stabilizing field from the magnets at the junction edge scales inversely with ALD layer thickness, in agreement with device-level free layer stability metrics showing improvements at lower ALD thicknesses. As the conformal ALD layer thickness is easily tuned, this technology provides flexibility in trading off reader amplitude and stability that should support scaling of the abutted TMR design out to 1 Tb/in² and beyond. [ABSTRACT FROM AUTHOR]