Texture induced noise and its impact on system performance

In this work, the effect of substrate texture on thin film disk noise and its impact on system performance are systematically examined. The surface structures of thin film disks with different substrate textures are characterized using Atomic Force Microscopy (AFM). Recording spectral analysis and AFM measurement yield disk surface parameters, surface roughness, correlation lengths of the texturing process both parallel and perpendicular to the texture line direction, and cross-hatch angle, all of which are used to characterize the texture noise. An error rate model that includes correlated texture noise is developed. Results are presented for various recorded patterns on disks with different textures. Error rate measurements are also performed. In general, it is shown that an improved system error rate results from a shorter perpendicular correlation length, smaller cross-hatch angle, and a smoother disk surface. The impact of texture on high density recording is also examined and discussed in detail.