Field emission noise caused by capacitance coupling ESD in AMR/GMR heads

We found field emission between the shield and the disk in AMR/GMR heads that was induced by a high voltage of the write driver. This paper discusses the mechanism of noise generation obtained using spin-stand, an electron beam probe measurement method and SPICE simulation. The source of noise in field emission is the current passing through the GMR element generated by capacitance coupling between the shield and the electrode. To prevent ESD/EOS damage to AMR/GMR heads, the effect of capacitance coupling between the GMR element and the write coil must be taken into account in the design of the AMR/GMR head structure for hard disk drives.