A novel MOS radiation dosimeter based on the MEMS-made oxide layer

This paper reports a novel MOS dosimeter with a very thick and defect-rich oxide layer fabricated by MEMS technology. We combined deep-reactive-ion etching (DRIE), thermal oxidation and LPCVD to prepare an oxide layer of 5μm containing multiple and large interfaces. Our devices were irradiated by γ-rays of ⁶⁰Co at 2Gy per minute for 2hrs and thermally stimulated current (TSC) method was used to determine the readout of dosimeters. Results show that there is a peak current about 450nA, indicating a total TSC charge of 158μC and sensitivity of 5.5nC/mm²·Gy, which is 40 times the sensitivity of previous MOS dosimeters.