Nanoscale depth-resolved electronic properties of SiO2/SiOx/SiO2 for device-tolerant electronics

Abstract

We have used nanoscale depth-resolved cathodoluminescence spectroscopy (DRCLS) of device-tolerant oxides to measure the energy levels and spatial distribution of defects within nanocrystalline grains in an α-SiO2 matrix that counteract hole trapping and reduce CMOS transistor degradation due to ionizing radiation. DRCLS of 58 nm SiO2/SiOx/SiO2 oxide structures distinguishes spatially and electronically between the intrinsic SiO2 and SiOx-related defects. Annealing the α-SiO2 oxide produces nanocrystalline Si grain formation that increases the concentration of defects 0.3 eV above the Si valence band that can trap electrons and block radiolytic proton transport. This study validates a carrier trapping mechanism for phase-separated device-tolerant SiOx oxide layers.