Threshold voltage shift of heteronanocrystal floating gate flash memory

2005 ◽  
Vol 97 (3) ◽  
pp. 034309 ◽  
Author(s):  
Yan Zhu ◽  
Dengtao Zhao ◽  
Ruigang Li ◽  
Jianlin Liu
Keyword(s):  
Threshold Voltage ◽  
Flash Memory ◽  
Floating Gate ◽  
Threshold Voltage Shift ◽  
Voltage Shift

Threshold Voltage Shift in Hetero-nanocystal Floating Gate Flash Memory

2004 ◽  
Vol 832 ◽  
Author(s):  
Yan Zhu ◽  
Dengtao Zhao ◽  
Ruigang Li ◽  
Jianlin Liu
Keyword(s):  
Threshold Voltage ◽  
Flash Memory ◽  
Oxide Thickness ◽  
Memory Device ◽  
Floating Gate ◽  
Threshold Voltage Shift ◽  
Voltage Shift ◽  
Poisson Boltzmann ◽  
Poisson Boltzmann Equation ◽  
Dot Density

ABSTRACTThe threshold voltage shift of a p-channel Ge/Si hetero-nanocrystal floating gate memory device was investigated both numerically and phenomenologically. The numerical investigations, by solving 2-D Poisson-Boltzmann equation, show that the presence of the Ge on Si dot tremendously prolongs the retention time, reflected by the time decay behavior of the threshold voltage shift. The increase of the thickness of either Si or Ge dot will reduce the threshold voltage shift. The shift strongly depends on the dot density. Nevertheless, only a weak relation between the threshold voltage shift and the tunneling oxide thickness was found. A circuit model was then introduced to interpret the behavior of threshold voltage shift, which agrees well with the results of the numerical method.

Numerical Simulations of Automatic Change of Threshold Voltage Shift in SRAM With Double-Floating-Gate Structures

2012 ◽  
Vol 59 (12) ◽  
pp. 3255-3262 ◽  
Author(s):  
Tetsufumi Tanamoto ◽  
Kosuke Tatsumura ◽  
Kiwamu Sakuma ◽  
Atsuhiro Kinoshita ◽  
Shinobu Fujita ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Threshold Voltage ◽  
Floating Gate ◽  
Threshold Voltage Shift ◽  
Voltage Shift

scholarly journals Analysis of Threshold Voltage Shift for Full VGS/VDS/Oxygen-Content Span under Positive Bias Stress in Bottom-Gate Amorphous InGaZnO Thin-Film Transistors

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 327
Author(s):  
Je-Hyuk Kim ◽  
Jun Tae Jang ◽  
Jong-Ho Bae ◽  
Sung-Jin Choi ◽  
Dong Myong Kim ◽  
...  
Keyword(s):  
Thin Film ◽  
Electric Field ◽  
Oxygen Content ◽  
Threshold Voltage ◽  
Thin Film Transistors ◽  
Electron Trapping ◽  
Threshold Voltage Shift ◽  
Voltage Shift ◽  
Drain Side ◽  
Bottom Gate

In this study, we analyzed the threshold voltage shift characteristics of bottom-gate amorphous indium-gallium-zinc-oxide (IGZO) thin-film transistors (TFTs) under a wide range of positive stress voltages. We investigated four mechanisms: electron trapping at the gate insulator layer by a vertical electric field, electron trapping at the drain-side GI layer by hot-carrier injection, hole trapping at the source-side etch-stop layer by impact ionization, and donor-like state creation in the drain-side IGZO layer by a lateral electric field. To accurately analyze each mechanism, the local threshold voltages of the source and drain sides were measured by forward and reverse read-out. By using contour maps of the threshold voltage shift, we investigated which mechanism was dominant in various gate and drain stress voltage pairs. In addition, we investigated the effect of the oxygen content of the IGZO layer on the positive stress-induced threshold voltage shift. For oxygen-rich devices and oxygen-poor devices, the threshold voltage shift as well as the change in the density of states were analyzed.

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