Modeling of current-voltage characteristics of metal/ultra-thin oxide/semiconductor structures

Fowler-Nordheim Current Oscillations Analysis of Metal/Ultra-Thin Oxide/Semiconductor Structures

“…It shows that this current increases with decreasing oxide thickness. By taking account of the results presented in [23], we conclude that when D ox decreases, S d increases and therefore the excess current increases.…”

“…However, we have shown in previous works [7,12,23] that on structures where the oxide thicknesses are ranging between 45 and 100 A, the behavior at low fields is different from that at high fields: -At low fields, the I-V g characteristics are of FN type and are affected by an excess current resulting from the degradation of the potential barrier at the metal/oxide interface by the presence of defects in the oxide layer. The effective area of these defects increases with the structure area.…”

“…Indeed, at low fields the excess current is more significant than the I FN F h m ; K h 1 À Á current particularly for the low thicknesses (lower than 60 A) or the great areas [7,23]. This enables us to neglect the oscillation amplitude of…”

“…The obtained values are represented in Table 1 [23]. Figure 5 shows the excess current I 0 exc F def m ; K def 1 À Á as a function of the oxide thickness.…”

“…In our case the disagreement can arise from this excess current, and the oscillatory behavior of the FN current cannot be modeled by the simple relation (14) by taking the conduction parameters at low or high fields. Theoretical (E th ) and experimental (E exp ) extrema (by taking account of the parameters presented in Table 1 Indeed, relation (17) shows that the oscillation factor B g of the experimental current is a function of the oscillation factors B exc , B o and the excess current which strongly depends on the structure area [23]. So, the displacement of the oscillation extrema with the structure area and the disagreement on the one hand between experiment and theory and on the other hand with the results of the literature can be related to the presence of the excess current.…”