Poole–Frenkel Emission Saturation and Its Effects on Time-to-Failure in Ta-Ta₂O₅-MnO₂ Capacitors

Abstract

I-V characterization of Ta-Ta2O5-MnO2 capacitors was investigated at different temperatures, and Poole–Frenkel (PF) emission saturation was experimentally observed. Under the saturation voltage, the I-V curves at different temperature converged, and the temperature dependency was vanished. Above the saturation voltage, the leakage current was decreasing as the temperature increased. In order to evaluate the effects of saturation voltages (VS) on time-to-failure (TTF) of the capacitors, VS were first determined at +2°C and +25°C, then voltage accelerating tests were conducted at 85°C under 1.6 times of rated voltage. The distribution of VS and TTF of the samples were plotted and compared. It was shown that samples with lower saturation voltage failed earlier in the distribution of time-dependent dielectric breakdown. Comparing conventional methods for evaluating the quality of tantalum capacitors by measuring the leakage current at elevated temperature, the nondestructive measurement of saturation voltage at +2°C and +25°C may provide a novel and practicing approach tool to screening out capacitors with defected Ta2O5 layers.

Electric-Field-Induced Metal Filament Formation in Cobalt-Based CBRAM Observed by TEM

“…The measured I–V curve showed >0.997 coefficient of determination R 2 with linear regression. The equation for the P–F emission is written as where μ is the electron mobility, N C is the density of states in the conduction band, E is the electric field intensity, ϕ T is the trap depth, k B is Boltzmann’s constant, T is the absolute temperature, and ε is the dielectric permittivity. , According to Figure d, the measured HRS current exhibits a positive temperature correlation and fits eq . The extracted trap depth of the P–F conduction is 0.53 eV and is consistent with the previously reported oxygen vacancy trap depth of the SiO x dielectric layer .…”

Coexistence of Electrochromism and Bipolar Nonvolatile Memory in a Single Viologen

“…The PFE phenomenon occurs for an electron dissociating from a neutral site, which leaves behind a positive site. The electron then escapes from the Coulomb potential of the positively charged site it left behind and reaches the conduction band of the insulator or semiconductor . So, the PFE model implies that with a combined effect of the thermal and applied external electric field, a massive amount of current (not essentially dominated by carrier mobility) can flow through the so-called insulating system as a result of carrier dissociation and trap release.…”

“…The electron then escapes from the Coulomb potential of the positively charged site it left behind and reaches the conduction band of the insulator or semiconductor. 42 So, the PFE model implies that with a combined effect of the thermal and applied external electric field, a massive amount of current (not essentially dominated by carrier mobility) can flow through the so-called insulating system as a result of carrier dissociation and trap release. This phenomenon is well established for explaining the switching of HRS to LRS for oxide as well as organic moleculebased resistive switching devices.…”

Modeling of Conduction Mechanisms in Ultrathin Films of Al2O3 Deposited by ALD

“…However, the density of defects or states in the oxide and semiconductor/oxide interface affects the electrical characteristics of MIS devices, including flat band voltage, dielectric breakdown, and conductivity. For this, the analysis of the conduction mechanisms (CMs) in oxide films by current-voltage measurements is fundamental to obtain parameters such as trap energy level in oxide, dielectric permittivity, oxide conductivity, and metal/semiconductor barrier energy [5][6][7][8]. Furthermore, the finite element method (FEM) models of semiconductor devices using the software Silvaco TCAD [9] can predict tunneling phenomena through thin oxides, improving the modeling of the dominant conduction mechanisms in MIS capacitors.…”