Nitrogen-concentration modulated interfacial and electrical properties of sputtering-derived HfGdON gate dielectric

Abstract

HfGdON thin films with different N concentrations have been deposited on Si (100) substrates using a radio frequency magnetron sputtering by changing the flow rate of N2 during deposition. Results have indicated that N doping could partly suppress the formation of the low-k SiOx interfacial layer in the interfacial region, which induces the evolution of the composition of interfacial layer changes from SiOx to the mixture of SiOx and silicate. Reduction in band gap and valence band offset and increment in conduction band offset have been detected with the increase of N doping content. Moreover, the best electrical properties including the highest dielectric constant (∼21.69), no obvious ΔVfb as well as the lowest leakage current density have been obtained with HfGdON films deposited at a N2 flow rate of 7 sccm. It can be concluded that N doping content should be carefully controlled to meet the best performance requirement for future complementary metal-oxide-semiconductor device.