Radiation tolerance and defect dynamics of ALD-grown HfTiO x -based MOS capacitors

Abstract

The study of radiation response and reliability of high-k dielectric materials plays a prominent role in Complementary Metal Oxide Semiconductor (CMOS) technology for device applications in nuclear and space electronics. In the present work, radiation effects on Atomic Layer Deposition (ALD)-grown Hafnium Titanium Oxide (HfTiO x )-based MOS capacitors have been investigated. HfTiO x thin films grown on Si substrates were irradiated with 60Co gamma radiation across a wide range of doses (100–3 Mrad). The defects in the pristine and gamma-irradiated thin films were examined by Photoluminescence spectroscopy. By using Poole-Frenkel tunnelling mechanisms, the effects of defects on the I–V characteristics of devices have been studied, as a function of radiation dose. Furthermore, the C–V measurements exhibit notable changes in the density of oxide and interface traps in the films. These devices survived gamma irradiation doses of up to 3 Mrad despite minor variations in their electrical properties. Hence, this work demonstrates the radiation tolerance and suitability of HfTiO x -based MOS capacitors for applications in radiation environments.