Generation of Si dangling bond defects at Si/insulator interfaces induced by oxygen scavenging. Issue 11 (6th October 2014) - Cerbu, F.
Abstract In this work we analyse the influence of the O‐scavenging process on interface traps in (100)Si/SiOx/HfO2(1.8 nm)/TiNx/Si stacks by using electrical measurements and electron spin resonance spectroscopy. The reduction of interfacial SiOx by high‐temperature annealing in O‐free ambient is found to lead to severe interface degradation exposed as generation of additional Si dangling bond defects (paramagnetic Pb0 centres). The density of these centres, well known to be electron traps impairing device operation, increases from ∼1 × 1012 cm−2 – the value typical for thermally oxidized Si – to >3 × 1012 cm−2 upon annealing at 1100 °C. This interface degradation is accompanied by the development of a hysteresis in the MOS capacitance–voltage curves indicating generation of additional oxide traps with areal density in the range of 1012 cm−2. However, the trap generation can be alleviated if the O‐scavenging annealing step is performed in helium ambient, suggesting formation of silicon monoxide molecules at the Si/SiOx interface as the origin of the observed trap generation.