Electrostatic discharge and electrical breakdown study of the head-disk interface in a hard disk drive

A systematic and comprehensive procedure for understanding electrostatic discharge and electrical breakdown at the head-disk interface in a hard disk drive is described. First, the resistance, breakdown and field emission behavior for the individual and combined carbon overcoat films on the disk and slider was determined through current versus voltage testing. Second, different electrostatic mechanisms that can produce a voltage difference between the disk and slider or read transducer were studied. Results are explained in terms of the relative time constants for the voltage on the head and disk. It is concluded that a potential difference between the disk and recording head as little as 2 V can result in electrical breakdown damage at the head-disk interface.