Semiconductor Science and Technology vol:29 issue:9 pages:095008-1-095008-6
A low-temperature multifrequency electron spin resonance (ESR) study has been carried out on Cz-(110)Si/insulator structures with organosilicate films of low dielectric constant kappa grown at 300 degrees C using the plasma-enhanced chemical vapor deposition method (PECVD). After subjection to a short-term UV-irradiation-assisted thermal curing treatment at 430 degrees C to remove the organic component from the low-kappa film and obtain optimal porosity, the NL8 ESR spectrum of C-2v symmetry is observed, characterized by g(1) (// = 1.999 83(8), g(2)(// = 1.992 74(8), g(3) = (//[ 1 (1) over bar0]) = 2.001 15(8). Based on previous insight, this reveals the generation in the c-Si substrate of singly ionized thermal double donor (TDD) defects with a core containing oxygen atoms. Remarkably, the generation is found to be highly nonuniform, and the defect density depth profile shows an exponential-like decay (decay length similar to 3.8 mu m) from the oxide/Si interface inward the Si substrate, thus exposing the defect formation as an interface-administered effect. Upon analysis, the strain induced by interfacial stress in the c-Si beneath the interface is suggested as the major driving component in the enhancement of TDD formation during thermal treatment, suggesting that substantial stress is involved with PECVD organosilicate low-kappa glasses. The result represents a different and affirmative illustration of the influence of strain on TDD formation. Based on the principal g values, the observed TDD is closest to the NL8(1) type, the one formed first in bulk c-Si through oxygen agglomeration during short-term thermal treatment.