ON A MICROELECTROMECHANICAL NONVOLATILE MEMORY CELL

An integrated nonvolatile memory cell based on micro-electro-mechanics is investigated. It consists of a thin micromachined bridge elastically deformed in such a way that it has two stable mechanical states to which the logical levels “0” and “1” are assigned. The state of the bridge can be changed using electrostatic forces and it may be read out by sensing the corresponding capacitance. The performance of such a device has been roughly estimated by a simple analytical model and first experimental samples have been fabricated using a slightly adapted MOS IC process. The results are very promising: the memory cells occupy an area about 10 times larger than the cells of a conventional RAM, are completely immune to electromagnetic fields and mechanical shocks, and the stored data are retained for an unlimited time. Switching voltages around 30 V have been achieved and a huge number of write cycles with low read/write times are expected. © 1990 IEEE