In perpendicular recording, substantial erasure of the stored data patterns could occur during writing process. Among all those erasure processes, the sidetrack erasure (STE) is one of the critical erasure issues. Nonetheless, unlike the adjacent track erasure (ATE) process, the locations of the sidetrack erasure are often many tracks away from the central writing track location. Such a STE process can cause some significant amplitude reduction of written data patterns after multiple writes. Subsequently the amplitude drop or the noise increase inevitably translates into a sizable bit error rate (BER) loss, resulting in severe degradation of the electrical performance of the disk drive. In some cases, the poor BER leads to a significant increase of unrecoverable errors and drive operation failure. Therefore, the STE has been a serious concern in both perpendicular drive integration process and perpendicular component design practice.
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