Materials Characterization and Microelectronic Implementation of Metal-insulator Transition Materials and Phase Change Materials

Vanadium dioxide (VO2) is a metal-insulator transition (MIT) material, and germanium telluride (GeTe) is a phase change material (PCM), both of which undergo several orders of magnitude increase in electrical conductivity from room temperature to their transition temperatures. They are candidates for many important technologies, including ultra-fast electronic memory, optical switches and filters, and active layers in terahertz metamaterials, among others. The physical mechanisms causing the phase transitions in these materials are explained and investigated experimentally. These materials were incorporated into six types of microelectronic devices, which were designed, fabricated, and tested at the Air Force Institute of Technology (AFIT). Additionally, these materials were investigated by materials characterization methods spanning the majority of the electromagnetic spectrum. The results show a most suitable applicability to electronic radio frequency (RF) switches, terahertz (THz) modulators, and phase change random access memory (PCRAM). Simple RF switches had 2 dB insertion losses and 30 dB of isolation, THz transmittance modulation of up to 99.5%, and PCRAM cells with threshold electric fields of approximately 1 V/ m