Dielectric materials are technologically important materials in the semiconductor industry used as gate oxides in metal oxide semiconductor field effect (MOSFET) transistors. Silicon dioxide and silicon nitride are studied extensively using cathodoluminescence (CL) to characterize the structure and electronic properties of point defect clusters.

In more recent years, CL continues to play an important role as high-κ dielectric materials replace SiO2. For example, depth-resolved CL spectroscopy can detect and locate defects and interfacial states within ultra-thin (<4 nm) gate oxides. In hafnium oxide, CL techniques detect the presence of several oxygen vacancy defects, their evolution during thermal processing, as well as the formation of hafnium silicates (HfSiO4) at the silicon-oxide interface. In LaLuO3, defects produced by LaLuO3–Si interdiffusion have been detected as well as suppression of these defects by monolayer thick Al2O3 interlayers.