Gamma-ray irradiation of ZnO thin film transistors and circuits

The radiation tolerance of electronic devices and circuits is of interest for space and some other harsh environment applications. Properly designed deep submicron gate length Si MOSFETs can have small threshold voltage shift and leakage increase for doses of 100 kGy (10 Mrad) or even larger [1], however polysilicon thin film transistors (TFTs) show significant changes at much lower dose (< 1 kGy) [2] and a-Si:H TFTs have volt-range threshold voltage shift for 10 kGy dose [3]. We report here the effects of gamma-ray irradiation on plasma enhanced atomic layer deposition (PEALD) ZnO TFTs and circuits. Devices and circuits function even after 1 MGy 60Co gamma ray exposure and radiation induced device changes are removed by a modest temperature (200 °C) anneal.