A low-temperature electron spin resonance study was carried out on thermal (110)Si/SiO2 as a function of oxidation temperature Tox with the intend to evaluate on atomic level the interface nature in terms of occurring inherent point defects which were at the origin of technologically detrimental traps. This revealed a remarkably high density of Pb-type interface centers (interfacial Si dangling bonds), which variant, based on coinciding electron spin resonance parameters, was typified as Pb0(110), close to Pb0(100) at the (100)Si/SiO2 interface. Starting at 7.5 x 1012/cm2, from Tox ≈ 700C onward, the density [Pb0(110)] gradually decreased by about 50% for Tox → 1100C - a result of global structural relaxation of the top SiO2 layer as exposed by several electron spin resonance parameters. In terms of Pb(0) centers, the (110) face was found to be the worst of all three low-index Si interfaces, i.e., [Pb0(100)] < [Pb(111)] < [Pb0(110)], over the range Tox < 900C. For Tox ≈ 900C, the (110)Si face did slightly improve over the (111)Si one, thus underlining the importance of Tox not only for such comparative defect studies but also for interface optimization.

Inherent Interfacial Si Dangling Bond Point Defects in Thermal (110)Si/SiO2, K.Keunen, A.Stesmans, V.V.Afanasev: Microelectronic Engineering, 2011, 88[7], 1492-4