Theory of charging and charge transport in “intermediate” thickness dielectrics and its implications for characterization and reliability

Abstract

Thin film dielectrics have broad applications, and the performance degradation due to charge trapping in these thin films is an important and pervasive reliability concern. It has been presumed since the 1960s that current transport in intermediate-thickness (IT) oxides ($10-100 nm) can be described by Frenkel-Poole (FP) conduction (originally developed for $mm-thick films) and algorithms based on the FP theory can be used to extract defect energy levels and charging-limited lifetime. In this paper, we review the published results to show that the presumption of FP-dominated current in IT oxides is incorrect, and therefore, the methods to extract trap-depths to predict lifetime should be revised. We generalize/adapt the bulk FP current conduction model by including additional tunneling-based current injection. Steady state characteristics are obtained by a flux balance between contacts and the IT oxide. An analytical approximation of the generalized FP model yields a steady state leakage current J ! exp(ÀBHE)(1 À CHE À D/E), where B, C, and D are material-specific constants. This reformulation provides a new algorithm for extracting defect levels to predict the corresponding charging limited device lifetime. The validity and robustness of the new algorithm are confirmed by simulations and published experimental data. V

Temperature effects on the bulk discharge current of dielectric films of MEMS capacitive switches

“…The hopping conduction, although present, plays a rather minor role in the presence of high electric fields [19]. The simultaneous action of the two mechanisms leads to a spatial charge distribution that was presented for first time in [20] and practically confirmed by a similar one, obtained by a different numerical approach and presented in [21].…”

Untitled

“…In this case study, the compact model is used for leakage and electron transfer current [37]. In this model, the energy band is divided to areas of R1, R2, R3 by trap depth, barrier height, and electric field as shown in Fig.…”

“…8. Energy band in compact model [37] Current transmission and electron leakage in a period of time is calculated by specifications of the dielectric and the following equations.…”

“…So, when the switch is turned on, dielectric charging will occur. According to [30,[36][37], already given, with the passage of time, the only parameter affecting the current transport and electron emission from dielectric will be the trapped electrons density (n T (y, t)). The following equation is used to calculate the change rate of this parameter: Table 2 istributions.…”

Multilayer electret activated by direct contact silicon electrode.

“…As this total trap density increases with lowering temperature, the interface electron trapping at the Si 3 N 4 /SiO 2 interface decreases [55]. Ultrathin films and films over 10nm take into consideration Trap Assisted Tunneling (TAT) [57,58].…”