A micro-electro-mechanical memory based on the structural phase transition of VO2


Corresponding author: e-mail nelsons@egr.msu.edu, Phone: 517-432-2130, Fax: 517-355-2288


The structural phase transition (SPT) in VO2 and its hysteretic behavior is used in the present work to program mechanical displacements of a micro-electro-mechanical memory through electro-thermal actuation (i.e., Joule heating). The memory element consists of a silicon dioxide cantilever with buried Ti/Pt heating electrodes and a nanocoating of VO2. The integrated heating electrode is used to actuate the structure, and its resistance is monitored to determine the phase transition of the material. A closed-loop system is implemented to ensure proper operation over a larger temperature window than previous work. The closed-loop control system is designed using the system parameters obtained from a static and transient response analysis. The advantages of the feedback configuration over an open-loop configuration are demonstrated by a larger difference between programmed states (i.e., higher noise margin). The micro-electro-mechanical memory shows no noticeable degradation after being operated for 12 000 cycles. Multiple mechanical states are programmed using oscillatory pulse sequences that produced bi-directional displacements. pssa201330021-gra-0001