Modeling of readback signal generated by scanning PCM surfaces

Micro-electro-mechanical systems (MEMS) based on Scanning Probe Methods (SPM) are an emerging technology for sensor based applications and data storage. Atomic Force Microscope (AFM) techniques with conductive tips, using phase-change materials to record data as amorphous or crystalline marks, have been demonstrated experimentally. Storing data patterns on the Phase Change Medium (PCM) is achieved by the write process, which determines the final shape and size of the mark based on complex electrical, thermal and phase transition phenomena. The read process relies on measuring the electrical resistivity at different positions of the respective mark. In this paper, we present the model of the readback signal that is generated when a data pattern stored in a PCM surface is scanned with constant velocity. The presented two-dimensional model is based on Finite Element Method (FEM) analysis that has been used to simulate such a physical mechanism. The main objective of this work is to derive and analyze the basic waveform of the readback signal from an amorphous mark, for different geometric and physical configurations of the storage system.