Trap concentration dependence on the electrical properties of annealed ultrathin fluorinated silicon oxides

In this study, the electrical properties of ultrathin (5-9 rim) liquid-phas e-deposited fluorinated silicon oxides (LPD-SiOFs) arc investigated under v arious annealing conditions. The electron tunneling current at E-ox = 4-6 M V/cm is suggested to be modeled by a generalized trap-assisted tunneling (G TAT) mechanism with consideration of trapezoidal- and triangular-barrier tu nnelings, This gives the trap concentration (N-t) and the trap energy level (Phi (t)) of a trapped oxide that is induced by fluorine incorporation. Th e reported Phi (t) of fluorine is around 1.98-2.2 eV while N-t for O-2-anne aled LPD-SiOF is I x 10(16)-3 x 10(18) cm(-3) and N-t for N2O-annealed LPD- SiOF is 5 x 10(14)-2 x 10(15) cm(-3), depending on the annealing conditions . The trap concentration within the LPD-SiOF film is demonstrated to decrea se with an increase in annealing temperature and time. From the GTAT modeli ng of O2- and N2O-annealed LPD-SiOF films, it is obvious that nitridation i n N2O can substantially reduce the concentration of traps (by an order of m agnitude of two) contained in original LPD-SiOF films. The flat-band voltag e shift, interface trap density, constant current stress (CCS), and constan t 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 an d modeling results, the traps are found to be strongly dependent on the imp urities contained in the oxide films (F or N atoms in this study). Using th e GTAT model, we can derive the trap energy level and trap concentration si mply from the current-voltage (I-V) characteristics without the use of othe r complicated measuring techniques.