Degradation of leakage currents and reliability prediction for tantalum capacitors

Abstract

Two types of failures in solid tantalum capacitors, catastrophic and parametric, and their mechanisms are described. Analysis of voltage and temperature reliability acceleration factors reported in literature shows a wide spread of results and requires more investigation.In this work, leakage currents in two types of chip tantalum capacitors were monitored during highly accelerated life testing (HALT) at different temperatures and voltages.Distributions of degradation rates were approximated using a general log-linear Weibull model and yielded voltage acceleration constants B = 9.8 ± 0.5 and 5.5. The activation energies were E a = 1.65 eV and 1.42 eV. The model allows for conservative estimations of times to failure and was validated by long-term life test data.Parametric degradation and failures are reversible and can be annealed at high temperatures. The process is attributed to migration of charged oxygen vacancies that reduce the barrier height at the MnO2/Ta2O5 interface and increase injection of electrons from the MnO2 cathode. Analysis showed that the activation energy of the vacancies' migration is ~ 1.1 eV.

Effect of an Interfacial Layer on Electron Tunneling through Atomically Thin Al2O3 Tunnel Barriers

“…After this traumatic BD event, the insulator becomes metallic with linear STS spectra. This form of dielectric BD is typical for crystalline insulators (>10s of nm thick) in capacitors . In the ultrathin regime of 1–2 nm, hard BD is primarily observed by STS for epitaxial Al 2 O 3 .…”

“…This form of dielectric BD is typical for crystalline insulators (>10s of nm thick) in capacitors. 40 In the ultrathin regime of 1−2 nm, hard BD is primarily observed by STS for epitaxial Al 2 O 3 . 36 Rather than gradual defect migration within the barrier, hard BD represents the breaking of the Al 2 O 3 bonds in the insulator.…”

Ordered clustering method and degradation trend analysis for performance degradation of tantalum capacitor

“…The tantalum capacitor is widely used in many fields, such as military, aerospace, and medical fields [1][2][3]. The performance of the tantalum capacitor directly influences the safe running of the system.…”