Inherent point defects in thermal biaxially tensile strained-(1 0 0)Si/SiO2 probed by electron spin resonance

Electron spin resonance studies are reported on (1 0 0)Si/SiO2 entities grown by thermal oxidation of biaxial tensile strained-(1 0 0)Si layers epitaxially grown on relaxed virtual substrates, with main focus on Pb-type interface defects, in particularly the electrically detrimental Pb0 variant. In the as-grown state a significant decrease (>50%) in interface defect density compared to the standard (1 0 0)Si/SiO2 interface was observed. As compared to the latter, this inherent decrease in electrically active interface trap density establishes strained Si/SiO2 as a superior device entity for all electrical properties in which (near) interface traps may play a detrimental role. For one, it may be an additional reason for the commonly reported mobility enhancement in strained silicon inversion layers and the reduction in 1/f noise. The data also confirm the admitted relationship between inherent incorporation of the Pb related interface defects and the Si/SiO2 interface mismatch.