Open AccessInvestigation on memory effect of MOS capacitors with Al2O3/Pt-nanocrystals/HfO2
Author(s) -
Yuewang Huang,
Gou Hong-Yan,
Liao Zhong-Wei,
Qingqing Sun,
Wei Zhang,
ShiJin Ding
Publication year - 2010
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.59.2057
Subject(s) - annealing (glass) , nanocrystal , materials science , capacitor , quantum tunnelling , electron , optoelectronics , capacitance , voltage , nanotechnology , condensed matter physics , electrical engineering , composite material , electrode , physics , engineering , quantum mechanics
Growth of Pt nanocrystals has been investigated by means of electron beam evaporation of Pt layer and post rapid thermal annealing. The results indicate that the density of nanocrystals increases first with the annealing temperature and the annealing timefollowed by a slight decrease. Uniformly distributed nanocystals with a density of 30×1011 cm-2 can be obtained in the case of the annealing at 800℃ for 20 s. Furthermemory effect of Al2O3/Pt nanocrystals/HfO2-based MOS capacitors has been characterizedindicating a capacitance-voltage C-V hysteresis window as large as 201 V in the sweep voltage range of -3—+8 V. In terms of the same programming timethe flat band voltage shift of the memory capacitor starts to increase remarkably when the programming voltage is increased to 9 V. This is related to a decrease in the energy barrier across the tunneling layer for electronsi.e.the tunnel mechanism of electrons is changed from direct tunneling to Fowler-Nordheim tunneling. Moreoverthe memory capacitor also exhibits a capability of continuous electron trapping with prolonging of the programming duration.