# Linear Dependence of Post-irradiation Input Bias Currents on Pre-irradiation Values in Silicon Bipolar Microcircuits

## TL;DR

This study demonstrates a linear relationship between pre-irradiation input bias currents and irradiation-induced degradation in silicon bipolar microcircuits, suggesting a new predictive approach for device damage based on initial bias measurements.

## Contribution

The paper reveals a universal linear dependence of irradiation effects on pre-irradiation bias currents and proposes a more accurate damage prediction method using these initial values.

## Key findings

- Linear dependence observed across different device types and irradiation conditions.
- Interface state energy distribution changes under irradiation explain the phenomenon.
- A new damage prediction method utilizing pre-irradiation bias values is proposed.

## Abstract

We find in experiments a linear dependence of ionization irradiation-induced degradations on pre-irradiation values of the input bias current in bipolar devices with simple input stages. The dependence is found to generally exist in all studied cases of different device types and different irradiation conditions. A unique behavior of the energy distribution of the interface states ($D_{it}$) under irradiation is suggested as the origin of the observed phenomenon: the generation of interface traps through the depassivation of Si-H bonds located near the pre-irradiation interface traps displays a $D_{it}$ as an enlarge of the initial $D_{it}$ and results in the general linear dependence. A more accurate damage prediction method by using the pre-irradiation values is proposed based on the observed phenomenon.