Structural and electrical properties of thin SiO2 layers grown by RTP in a mixture of N2O and O2
Ultrathin (less than 10 nm) dielectric films for the application in metal-oxide-semiconductor (MOS) devices have been fabricated in a O2:N2O atmosphere using rapid thermal processing (RTP). It will be shown that with increasing N2O-content in the mixtures of N2O and O2 the oxide thickness decreases and the interfacial nitrogen concentration increases. Therefore, the nitrogen concentration at the Si/SiO2 interface, responsible for improved electrical characteristics, is adjustable by the O2:N2O ratio. High charge-to-breakdown (Q(sub)BD) values comparable to oxides processed in pure N2O atmosphere are obtained for electron injection from the Si-substrate. For electron injection from the gate, the Q(sub)BD-values are considerably higher. For a O2:N2O ratio of 3:1 the highest Q(sub)BD-values have been obtained together with a very homogeneous Q(sub)BD-distribution across the wafer.