Thin film head with contoured pole face edges for undershoot reduction

Abstract

A thin film magnetic read/write head is manufactured using Al.sub.2 O.sub.3 dams. The Al.sub.2 O.sub.3 dams are formed using a sacrificial layer which is deposited upon a bottom pole layer. An Al.sub.2 O.sub.3 layer is deposited over the sacrificial layer. When the sacrificial layer is removed, the Al.sub.2 O.sub.3 layer forms dams between which a top pole piece is deposited. The sacrificial layer is removed using lapping and a selected chemical etch; etch of the sacrificial layer which lifts-off overlying partial lapping or chemical etch followed by chemical Al.sub.2 O.sub.3 ; depositing photoresist dams and chemically, etching the encapsulation layer and the sacrificial layer; or removal through physical or thermal shock of the Al.sub.2 O.sub.3 layer sputtered at zero bias followed by a selective chemical etch of the sacrificial layer. The thin film magnetic head of the present invention has pole tips which provide an outside pole face contour that is significantly different from a pole tip contour along a gap region. This reduces an undershoot effect in readback pulses in a readback signal. The altered contour can be used on both top and bottom pole tips to eliminate both leading and trailing undershoots. Additionally, in shielded probe heads for vertical recording a gap region contour can be altered to achieve a similar reduction in leading undershoot.