Development of BDFO or ZnO thin Film technology to Gate Dielectric and Microcantilever Energy Scavenger Applications

Abstract

Energy scavenging is attractive to use in powering miniature sensors and devices since newlineregular energy sources (i.e., batteries) impose severe limitations in size, weight, and newlineoperational lifetime. Among several alternatives to conventional batteries, piezoelectric newlineenergy-harvesting devices based on mechanical vibration have attracted considerable attention newlineas a stable and continuous power supply to micro and nano devices. newlineZinc oxide (ZnO) is used here as piezoelectric material which is one of the pollutionfree newlinepiezoelectric materials and it is free from limitations found with Lead zirconate titanate newline(PZT). Magneto electric (M-E) multiferroic Dy modified BiFeO3 (Bi0.7Dy0.3FeO3 or BDFO) is newlineone such rare material exhibits the ferromagnetism, ferroelectricity and piezoresponse at room newlinetemperature. These newly developed BDFO and ZnO are multifunctional materials, which newlinehave opened the path for new possibilities in MEMS device fabrication. Therefore, it is newlineessential to further investigate the important properties of combination of dielectric/ newlinesemiconductor (BDFO/ZnO) interface before using in device fabrication. newlineThe present thesis explores the properties of Multiferroic/Semiconductor (BDFO/ZnO) newlinecombination in MIS (Metal/Insulator/Semiconductor) systems and the development of newlinepiezoelectric energy scavengers (for ambient vibrations). A hybrid (multiferroic/ newlinesemiconductor) approach combining properties of BDFO and ZnO, to satisfy the desired newlinerequirement of alternative gate dielectric material to SiO2 for the fabrication of MIS Capacitor newlineis presented in this thesis. Secondly the fabrication and characterization of novel piezoelectric newlinezinc oxide (ZnO) thin film microcantilever energy scavenger with wet etching and lift off newlineprocess is also presented. newlineProposed MIS structure of Cr-Au/BDFO/ZnO/p-Si is fabricated by depositing BDFO newlinethin films on ZnO/Si films using pulsed laser deposition (PLD). The electrical properties of newlinethe fabricated MIS device and their interface traps are investigated at room temperature.