Yan Liu

Emerging thin film technology

Xidian University, Xi’an, China

Email: xdliuyan@xidian.edu.cn

Biography

Prof. Yan Liu is currently a professor and Ph.D. supervisor in the School of Microelectronics, Xidian University.  She has been selected as a Huashan Scholar of Xidian University. She is a reviewer for international professional journals such as IEEE Electron Device Letters, IEEE Transaction on Electron Devices, and Optics Express. She has been engaged in the research of CMOS microelectronic devices and nanometer optoelectronic devices for a long time, mainly research interests include ferroelectric field-effect transistors based on Group IV materials, high mobility material MOSFETs, and silicon-based optoelectronic devices. She has authored or coauthored more than 100 papers in top conferences and mainstream journals of semiconductor device physics, including International Electron Devices Meeting (IEDM), IEEE Transaction on Electron Devices, IEEE Electron Device Letters, Opto-Electronic Advances, Optics Express, etc. She has been the leader of the key projects of the National Major Research Program and the key R&D projects of the Ministry of Science and Technology. She is the holder of more than 20 granted patents.. 

Abstract for Presentation

Non-Volatile Mobile-Ionic Transistors with Amorphous Gate Dielectrics

The ferroelectric-based devices have attracted extensive attention for memory and neuromorphic computing applications due to the CMOS compatibility and the better scalability of doped-HfO2 ferroelectric materials. However, the ferroelectric field-effect transistors (FeFET) still face the problems of limited endurance due to the FE phase change and the charge trapping during the polarization switching. Besides, the ferroelectric behavior also can be observed in the amorphous dielectric (ZrO2, Al2O3, HfO2, etc.), considered as mobile ion related, and non-volatile Mobile-Ionic FET (MIFET) has been demonstrated with an ultra-scaled amorphous gate insulator. This talk will give an overview of the mechanism of amorphous oxide-based ferroelectric and MIFET with various amorphous oxide for non-volatile memory and analog synapse application. For the physical origin of the FE-like behaviors, this talk will illustrate through electrical characterization as well as numerical simulation of amorphous oxide capacitors, demonstrating that it originates from the migration of the mobile ions.  Besides, this talk will present the state of the art of MIFET for memory, including operation voltage, endurance, and retention. Moreover, the temperature dependency of the MIFETs will also be discussed, which exhibits essential differences from HfO2-based FeFETs. Thanks to the modulation of mobile ions, this talk will illustrate that the MIFET can be utilized for analog synapse with superior symmetry and linearity for both potentiation and depression, and demonstrated for convolutional neural network (CNN) and spiking neural network (SNN) application. MIFET with amorphous gate dielectrics as a novel technology can be used for ultra-scaled memory and neuromorphic computing systems.