Shijin Ding

Emerging thin film technology

School of Microelectronics, Fudan University, Shanghai, China

Email: sjding@fudan.edu.cn

Biography

Dr. Shi-Jin  Ding is a professor of the school of microelectronics, Fudan University, and vice director of Jiashan Fudan Institute.  He received the Ph.D. degree from Fudan University in 2001. After that, he  worked  as research fellow of the Alexander von Humboldt Foundation in Kiel University of Germany, and then as research fellow in National University of Singapore.  He joined Fudan University in 2005, and became Full  Professor  in  2008.  His  current  research  interests  include  metal-oxide semiconductor-based  field-effect  transistors  and  memories,  atomic  layer deposition/molecular  layer  deposition  of  nanofilms  and  nanodots  for  integrated circuits and other electronic devices. 

Abstract for Presentation

Semiconductor Nanofilms/nanodots for Electronic Devices

In this talk, some emerging fabrication methods  will be introduced for  semiconductor nanofilms and nanodots which can be used for switching devices, memory devices and chemical  sensors.  Firstly,  I  will  introduce  the  growth  of  InOx  nanofilms  by  thermal atomic  layer  deposition  (TALD)  and  plasma-enhanced  atomic  layer  deposition (PEALD) using different precursors, which are used as the channel layers of thin-film transistors  (TFTs).  In  particular,  the  effect  of  the  channel  thickness  on  the  TFT performance will be discussed  in detail. Meanwhile, to improve the device performance, various  post-treatment  techniques  are  explored.  Therefore,  high  performance  TFTs have been  achieved, including  near-zero-threshold-voltage, a very small subthreshold slope  of 69 mV/dec, a very high  ON/OFF current ratio of ~10 10 , and relatively high field  effect  mobility  of  17  cm 2 /Vs.  Secondly,  molecular  layer  deposition  will  be introduced  to  prepare  ultrathin  organic  semiconductor  films  of  polythiophene  under precise  control.  The  resulting  nanoscale  ultrathin  films  presented  a  good  thickness uniformity and smooth surface, in contrast to the uneven porous structure of spin-coated films.  Further, the fabricated gas sensor using the above polythiophene film as an active layer exhibited a 17%/ppm sensitivity to ammonia and a response time of less than 2 s, which is much superior to its counterpart with the spin-coated polythiophene film and is the best performance compared to previous reports. Lastly,  different compositional halide  perovskite  (CsPbX3)  quantum  dots  (PQDs)  were  obtained  by  thermal evaporation  deposition  under  precious control.  By using  different bandgaps  PQDs as stepped floating gates, the fabricated transistors exhibit nonvolatile multilevel memory states written/erased by electrical and high-bandwidth optical signals. Meanwhile, the device can also realize logic functions such as an optoelectronic AND gate by separably programming the states of the stepped floating gates with bias and optical wavelength. A convergence of multilevel logic computing and storage is further achieved on the transistor.

References

[1]  Q.  Ma, H.-M.  Zheng, Y .  Shao, B.  Zhu, W.-J.  Liu*,  S.-J.  Ding*  and D. W.  Zhang,  Nanoscale Res. Lett. (2018) 13:4

[2] Q. Ma, Y . Shao, Y.-P. Wang, H.-M. Zheng, B. Zhu, W.-J. Liu , S.-J. Ding*, and D. W. Zhang,  IEEE Electron Device Lett., 39 (2018) 1672

[3]  D.-Q.  Xiao,  B.-B.  Luo,  C.-M.  Huang,  W.  Xiong,  X.  Wu*,  S.-J.  Ding*,  IEEE  Trans.  Electron Devices, DOI: 10.1109/TED.2022.3173249

[4]  H. Tan, Y .  Chu, X. Wu*, W .-J.  Liu, D. W.  Zhang, and S.-J.  Ding*,  Chem. Mater.,  2021, 33  (2021) 7785

[5] J. Pei, X. Wu*, W.-J. Liu, D. W. Zhang, and S.-J. Ding*, ACS Nano 16 (2022) 2442