Dose rate effects in bipolar oxides: Competition between trap filling and recombination

Abstract

Predicting the low-dose-rate degradation of bipolar technologies is one of the main issues for circuits intended for use in the ionizing-radiation environment of space because of the enhanced low-dose-rate sensitivity (ELDRS). In this letter, ELDRS is shown to be related to competition between trapping and recombination of radiation-induced carriers in the oxide. The presented model is shown to be in good agreement with experimental data. It is also shown that this effect is strongly dependent on the oxide quality.

Experimental demonstration of the switching dose-rate method on doped optical fibers

“…2.a), taking into account valence and conduction bands, an electron-trap population at a given energy level, and a recombination-center population inside the material's gap. Because of the involved transition probabilities, the trap and the recombination center populations are coupled by way of the conduction band [10]. This coupling is the point that makes this model different to the classical power-law models, that consider only independent traps.…”

“…The ELDRS does not suggest any intuitive quick test method for doped optical fiber, and a priori supposes a real-time (15 years) test for doped fiber assessment for a real space mission. This problem is however well-known in bipolar transistors for which the increasing degradation at low-dose rate is mainly due to passivation oxides [10]. For these devices, a short-time test method -the Switching Dose Rate Method -has been developed.…”

“…Many models, based on quite different physical bases, can predict ELDRS and lead to similar degradation tendencies versus the dose rate [10,11,12]. Therefore, we use in this paper the historical R. Chen's model [10] as fig.…”

“…Therefore, we use in this paper the historical R. Chen's model [10] as fig. 2.a), taking into account valence and conduction bands, an electron-trap population at a given energy level, and a recombination-center population inside the material's gap.…”

Total ionizing dose effects of domestic SiGe HBTs under different dose rates

“…Due to the competition between the oxide trap charge and interface trap charge according to the literature [10], there has more interface trap charge induced by the prolonged low dose rate irradiation, while more oxide trap charge induced by the high dose rate. And for the different devices fabricated by the different process, the amounts of the oxide trap charge and interface trap charge induced by radiation may different because of the amounts of the defects introduced in the oxide.…”