Recording on PZT and AgInSbTe thin films for probe-based data storage

In this paper, we propose microprobe-based eletrical and thermal recording techniques for the application of high-density data storage. A microheater integrated at the free end of a thermal microprobe is formed by diffusion of boron for 3 hrs at 1160 degreesC and it is supported by two contuctive silicon legs. When flowing a pulsed current through the legs, the heater is electrically heated up in a short time. Primary experiments for the electrical and thermal recording are evaluated using a sol-gel processed PZT and AgInSbTe thin films as a storage medium. For electrical recording on the PZT film, a voltage pulse is applied between a conductive tip and the PZT film. The nano-sized ferroelectric domains are easily switched by the applied voltage, The smallest marks were below 100 nm in diameter, which correspond to bit densities over 70 Gb/in(2). For the thermal recording on the AgInSbTe, the conductive tip is Joule heated by flowing a current and then the heated tip makes a local phase change (amorphous to crystalline or amorphous to crystalline) of the AgInSbTe thin film. To read the formed mark, we measure an electrical resistance between a bottom electrode of AgInSbTe and the conductive tip because the electrical resistance of amorphous state is higher than that of the crystalline state.