Song S. Xue

Thermally stable spin valve films with synthetic antiferromagnet pinned by NiMn for recording heads beyond 20 Gbit/in.2

The thermal stability of spin valve films with synthetic antiferromagnet (SAF) pinned by antiferromagnetic IrMn, NiO, and NiMn layers were studied. The SAF layer enhances the thermal stability in general; however, the blocking temperature (and the blocking temperature distribution) of the antiferromagnet is still important for the magnetic rigidity of the pinned layer. Once the temperature reaches the blocking temperature the SAF layer can go into either the spin flip or flop state, depending upon the magnetic moment ratio of the reference layer and pinned layers. The GMR linear head response can be distorted for nonlinearity. The NiMn pinned SAF structure shows magnetic and thermal stability which makes it practical for the real products. A high GMR of 11% can be obtained in both bottom and top NiMn SAF spin valves by advanced processes. Recording heads were built using such stacks which demonstrated recording areal density of 20 Gbit/in.2 and beyond.

Study of SiOxNy as a bottom antireflective coating and its pattern transferring capability

To meet such challenges for the controlling of critical feature dimension at sub-50–100‐nm, it has been a general industrial trend to employ shorter wavelength (193nm, for example) lithography for better resolution and to use bottom antireflective coating (BARC) for a reduced standing wave formation and thus, a better critical dimensional control. Matching the optical constants (n,k) between the BARC, photoresist, and the underlayer to be patterned is critical for the elimination of such standing waves. SiOxNy and SiOxCy are two attractive inorganic BARC candidates in view of their easily adjustable optical constants by varying the deposition parameters and their etching compatibility with standard semiconductor plasma processes. In this article, SiOxNy films were prepared by plasma enhanced chemical vapor deposition approach. These films have been further characterized using x-ray photoelectron spectroscopy for chemical composition depth profile, Fourier transform infrared spectroscopy for local chemical...

Effect of magnetostatic coupling between free and reference layers on the thermal stability of synthetic spin valves

A relationship between initial ferromagnetic magnetostatic coupling strength (H/sub F/) and a long-term thermal stability of the spin valve (SSV) sensors was investigated. The thermal degradation in GMR properties of SV stacks is more apparent in the stack exhibiting a higher initial H/sub F/, and is expedited for the stacks without capping layers. Initial H/sub F/ values appear to be one of the good indicators for the long-term thermal stability of SV stacks since they reflect the inter-layer microstructure of SV sensor stacks. The origin of H/sub F/ is also discussed by comparing measured H/sub F/ values with estimated ones.