Characterizing Metal Insulator Transition (MIT) Materials for Use as Micro-Switch Elements

Abstract

Metal insulator transition (MIT) materials, or phase change materials (PCM) are material compounds that have the ability to be either conductors or insulators. Vanadium dioxide (VO2) and germanium telluride (GeTe) exhibit such a transition property. These materials have ferroelectric properties as well as a variable resistivity. The ability to vary the resistance of a single material is useful when designing integrated circuits on the micro scale. By varying the temperature or the electric field across these materials, we are able to change the resistivity within a portion of a line. This can in turn be used to create a switch within a wire. In order to measure these changing properties, we developed novel surface micromachined test structures capable of using a variety of MIT materials. By varying the electric field or the thermal gradient across an area of the wire segment, we were able to adjust the resistivity of the material. Therefore, by tailoring the properties of specific portions of a conductor, we were able to control current flow in a circuit without needing a micro-mechanical or a microelectronic device.