UV-ENHANCED OXY-NITRIDATION OF SEMICONDUCTOR SUBSTRATES

摘要

The oxynitride or oxide layer is formed on a semiconductor substrate by subjecting the substrate to UV radiation while exposed to a gaseous atmosphere Of' 02 and one or more of N2, N20, H2 and NH3. Thereafter, a silicon nitride layer is formed according to known 4-step gate stack dielectric processing techniques. Alternatively, a 3-step gate stack process is used, namely following UV-oxidation, a further UV­radiation in NH3 may be applied, followed by a rapid thermal anneal process in an inert ambient. By using UV-oxidation as the first step in either a 4-step or 3-step gate stack process, very thin composite dielectric films with equivalent oxide thickness (EOT) below 16A and as low as 14.2A can be obtained with significant improvement in leakage current density. 178686v2(CB)