Eric Cheuk Wing Leung

Reliability of tunneling magnetoresistance recording head-lifetime, failure mode, and production screening

We have studied the behavior of failure in lifetime acceleration test of TMR prototype with performance meeting 100 Gb/in/sup 2/ recording. The failure mode is identified to be same as extrinsic breakdown of the AlOx barrier, while failure due to magnetic change is not observed. The extrinsic breakdown is further found to be the increase in pinhole conduction in the barrier, involving thermal energy from ambient and read current. Results also suggest the existence of a critical voltage below which pinhole is not enlarged. Furthermore, we will discuss our hypothesis in the formation of pinholes and the role of charge traps in the barrier. Finally, we will discuss a method for screening out heads with relatively short lifetime, which is feasible for mass production. The screening allows a guarantee of lifetime well enough for drive application.

Anti-Static Robustness Enhancement and High-Frequency Noise Pickup Immunity by Internal Shunting for Tunneling Magnetoresistive Sensors

Internal shunting is introduced on tunneling magnetoresistive heads to enhance device anti-static robustness and external high-frequency noise pickup immunity. The details of the shunting scheme and the mechanism leading to both anti-static robustness and reduced high-frequency noise pickup are discussed.

Writer performance improvement in MR head with over-sized trailing poles technique

A new inductive writer design for MR head with a trimmed and planarized top shield and an over-sized trailing pole is presented. The normal P2 pole is located right above the trimmed top shield. Modeling has been conducted on the write field fringing for this new design. It shows that the field distribution pattern is just a reverse image of the traditional MR write head. With this new design, the straight fringe pattern is located at the trailing side and a better written track is expected due to the elimination of the curved write field fringing in a traditional head. The actual samples were fabricated and their performance was evaluated by MFM image. The result shows the written track is straight with nearly zero erase band. The track width is independent of the bit density as expected.