In this study, the electrical properties of ultrathin (5-9 nm) liquid-phase-deposited fluorinated silicon oxides (LPD-SiOFs) are investigated under various annealing conditions. The electron tunneling current at Eox = 4-6 MV/cm is suggested to be modeled by a generalized trap-assisted tunneling (GTAT) mechanism with consideration of trapezoidal- and triangular-barrier tunnelings. This gives the trap concentration (Nt) and the trap energy level (Φt) of a trapped oxide that is induced by fluorine incorporation. The reported Φt of fluorine is around 1.98-2.2eV while Nt for O2-annealed LPD-SiOF is 1 × 1016-3 × 1018 cm-3 and Nt for N2O-annealed LPD-SiOF is 5 × 1014-2 × 1015 cm-3, depending on the annealing conditions. The trap concentration within the LPD-SiOF film is demonstrated to decrease with an increase in annealing temperature and time. From the GTAT modeling of O2- and N2O-annealed LPD-SiOF films, it is obvious that nitridation in N2O can substantially reduce the concentration of traps (by an order of magnitude of two) contained in original LPD-SiOF films. The flat-band voltage shift, interface trap density, constant current stress (CCS), and constant voltage stress (CVS) all show that LPD-SiOF annealed in N2O has the best material quality in comparison with others. As shown in the experimental and modeling results, the traps are found to be strongly dependent on the impurities contained in the oxide films (F or N atoms in this study). Using the GTAT model, we can derive the trap energy level and trap concentration simply from the current-voltage (I-V) characteristics without the use of other complicated measuring techniques.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)