Charge Trapping Memory Cell of TANOS (Oxide-SiN-Al₂O₃-TaN) Structure Erased by Fowler-Nordheim Tunneling of Holes

Abstract

We present the TANOS (Si-Oxide-SiN-Al 2 O 3 -TaN) cell with 40 Å-thick tunnel oxide erased by Fowler-Nordheim (FN) tunneling of hole. Thanks to introducing high-k dielectrics, alumina (Al 2 O 3 ) as a blocking oxide, the erase threshold voltage can be maintained to less than -3.0 V, meaning hole-trapping in SiN. We extracted the nitride trap densities of electron and hole for the TANOS cell. It is demonstrated that the TANOS structure is very available to investigate the trap density with shallower energy. The energy level of hole trap (1.28 eV) is found to be deeper than that of electron (0.8 eV). As the cycling stress is performed, persistent hole-trapping is observed unlike endurance characteristics of conventional floating-gate cell. The hole trapping during the cycling stress can be attributed to two possibilities. The injected holes are trapped in neutral trap of tunnel oxide and residue of holes which is not somewhat compensated by injected electrons may be accumulated in SiN. It is demonstrated the erase operation of the TANOS cell is governed by Fowler-Nordheim tunneling of hole due to the field concentration across the tunnel oxide.

Global and local charge trapping in carbon nanotube field-effect transistors

“…The observation that μ CNTFET of transfer curves with applied pulse 1 is larger than that with applied pulse 2 may suggest that (1) pre-trapped holes have less effect on hole transport than pre-trapped electrons, or/and (2) the number of pre-trapped holes is much smaller than that of pre-trapped electrons. The latter suggestion is consistent with Lee et al's findings [25], where the number of trapped electrons is much larger than that of trapped holes in the Si 3 N 4 film. However, for the electronconduction branches, μ CNTFET under the influences of both pulse 1 and pulse 2 are comparable.…”

Correlation between in Situ Raman Scattering and Electrical Conductance for an Individual Double-Walled Carbon Nanotube

“…After the surface passivation with the Si 3 N 4 layer, an ambipolar characteristic with a stable hysteresis loop in the transfer curve is observed for V gs in a range of −20 to +20 V, as shown in Figure a. The observed p-type to ambipolar conversion can be attributed to the removal of oxygen adsorbed on the DWNT channel by coating Si 3 N 4 . , This is consistent with the findings that desorption of oxygen by dielectric layer passivation or annealing CNTFETs in vacuum or inert gas promotes conversion from p- to ambipolar or even n-type. ,, In addition, it has been reported that the SiO 2 −Si 3 N 4 stacks play the role of trapping centers for both electrons and holes . The hysteresis loop is caused by the trapping/detrapping of electrons/holes in the trapping centers, and it is stable after passivation.…”

“…4,13,14 In addition, it has been reported that the SiO 2 -Si 3 N 4 stacks play the role of trapping centers for both electrons and holes. 15 The hysteresis loop is caused by the trapping/detrapping of electrons/holes in the trapping centers, and it is stable after passivation. Since our Raman spectra are collected from the center of the DWNT channel, the results of the Raman scattering should reflect the energy band shift (or, in an equivalent way, the Fermi level ε f shift) in the DWNT channel rather than any influences from the source and drain contacts.…”

Electron Transport in Carbon Nanotubes

“…28 In addition, it has been reported that the SiO 2 -Si 3 N 4 stacks act as the trapping centers for both electrons and holes. 153 The hysteresis loop is caused by the trapping/detrapping of electrons/holes in the trapping centers and it is stable after passivation. Since our Raman spectra are collected from the center of the DWNT channel, the results of the Raman scattering should reflect the energy band shift (or, in an equivalent way, the Fermi level ε f shift) in the DWNT channel rather than any influences from the source and drain contacts.…”