A comparative electron spin resonance study was reported on (100)Si/SiO2 entities, grown by thermal oxidation of biaxial tensile strained (100)Si (sSi) layers, epitaxially grown on a strain relaxed Si0.8Ge0.2 buffer layer, and standard (100)Si. In the as-oxidized state a significant decrease (~50%) of inherently incorporated interface defects, Pb0 and Pb1, was observed, i.e., the sSi/SiO2 interface was found to be inherently significantly improved in terms of electrically detrimental interface traps (Pb0). After vacuum-ultraviolet irradiation two more SiO2-associated defects appear, namely Eγ’ (generic entity O3≡Si·) and EX. Interestingly, a decrease (~50%) of Eγ’ defect density was observed compared to standard Si/SiO2. This reduction in inherent electrically active interface (Pb0) and near-interface (Eγ’) traps would establish sSi/SiO2 as a superior device structure for all electrical properties where (near)-interfacial traps play a detrimental role. For one, the reduction of detrimental (near)-interface defects may be an additional reason for the commonly reported mobility enhancement in sSi/SiO2 based metal–oxide–semiconductor structures over standard Si/SiO2 ones, and at the same time account for the reported reduction of 1/f noise in the former structures. The data also confirm the generally accepted notion that Pb-type defects were mismatch induced defects.

Paramagnetic Point Defects at Interfacial Layers in Biaxial Tensile Strained (100)Si/SiO2. P.Somers, A.Stesmans, V.V.Afanasev, C.Claeys, E.Simoen: Journal of Applied Physics, 2008, 103[3], 033703