Nanoscale Investigation of the Piezoelectric Properties of Perovskite Ferroelectrics and III-Nitrides

pyroelectric;piezoelectric;polarity;polarization;EFM;SKPM;PFM;piezoresponse;nanoscale characterization;ferroelectric;III-Nitride;SPM;AFM;NVFRAM;PZT;GaN;FRAM

Rodriguez, Brian Joseph ; Angus Kingon, Committee Co-Chair,Robert Nemanich, Committee Chair,Salah Bedair, Committee Member,Jacqueline Krim, Committee Member,Alexei Gruverman, Committee Member,Rodriguez, Brian Joseph ; Angus Kingon ; Committee Co-Chair ; Robert Nemanich ; Committee Chair ; Salah Bedair ; Committee Member ; Jacqueline Krim ; Committee Member ; Alexei Gruverman ; Committee Member

University:North Carolina State University

关键词: pyroelectric;    piezoelectric;    polarity;    polarization;    EFM;    SKPM;    PFM;    piezoresponse;    nanoscale characterization;    ferroelectric;    III-Nitride;    SPM;    AFM;    NVFRAM;    PZT;    GaN;    FRAM;   

Others  :  https://repository.lib.ncsu.edu/bitstream/handle/1840.16/3199/etd.pdf?sequence=1&isAllowed=y

美国|英语

来源: null

【 摘 要 】

Nanoscale characterization of the piezoelectric and polarization related properties of III-Nitrides by piezoresponse force microscopy (PFM), electrostatic force microscopy (EFM) and scanning Kelvin probe microscopy (SKPM) resulted in the measurement of piezoelectric constants, surface charge and surface potential.Photo-electron emission microscopy (PEEM) was used to determine the local electronic band structure of a GaN-based lateral polarity heterostructure (GaN-LPH). Nanoscale characterization of the imprint and switching behavior of ferroelectric thin films by PFM resulted in the observation of domain pinning, while nanoscale characterization of the spatial variations in the imprint and switching behavior of integrated (111)-oriented PZT-based ferroelectric random access memory (FRAM) capacitors by PFM have revealed a significant difference in imprint and switching behavior between the inner and outer parts of capacitors. The inner regions of the capacitors are typically negatively imprinted and consequently tend to switch back after being poled by a positive bias, while regions at the edge of the capacitors tend to exhibit more symmetric hysteresis behavior.Evidence was obtained indicating that mechanical stress conditions in the central regions of the capacitors can lead to incomplete switching. A combination of vertical and lateral piezoresponse force microscopy (VPFM and LPFM, respectively) has been used to map the out-of-plane and in-plane polarization distribution, respectively, of integrated (111)-oriented PZT-based capacitors, which revealed poled capacitors are in a polydomain state.