Multifunctional Micro-Mechanical Memory Devices

Two types of micro-mechanical memory cells are introduced in this paper. The programmable parameters are the resonant frequency of a micro-mechanical bridge and the tip deflection of a micro-mechanical cantilever. For both cases, the actuation was done by laser pulses that locally heated the vanadium dioxide (VO₂) thin film coating. Due to the hysteretic behavior of the mechanical properties of the VO₂ film coating across the transition, a different “memory state” was programmed with every pulse. The memory state remained programmed after the pulse ended, as long as the sample was maintained at a specific temperature (programming temperature) by using a Peltier heater. The resetting of the mechanical memory cell was accomplished by driving the temperature to regions outside the hysteretic region.