The Effect of Rapid Thermal Annealing on the Quality of Thin Thermal Oxides

Rapid thermal processing (RTP) as a post oxidation annealing (POA) process is of considerable influence on the quality of thin thermal oxides: The number of defect related oxide failures is reduced whereas the intrinsic oxide quality is slightly reduced but to a degree that is of no importance with respect to reliability aspects. It is important to perform POA after poly-Si deposition and doping, while POA after poly-Si patterning was found to be a critical process. Infrared spectroscopy indicates stress relaxation due to the POA-treatment but no change of the SiO2/Si interface roughness could be observed by high resolution electron microscopy. The improvement of the oxide quality is accompanied by the creation of electron traps in the oxide.