Generation of Si dangling bond defects at Si/insulator interfaces induced by oxygen scavenging

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.

High-kgadolinium scandate on Si obtained by high pressure sputtering from metal targets andin-situplasma oxidation

“…Furthermore, scavenging the interface has the detrimental effect of severely increasing the interface trap density: for the Ti devices the D it is high (∼10 13 eV −1 cm −2 ) due to the formation of additional dangling bonds, as has been reported in other works on scavenging [25,54,55]. This value is almost two orders of magnitude higher than the Pt case, which was 3×10 11 eV −1 cm −2 .…”

“…Figure 13: C-Vgate characteristics of capacitors with Gd0.9Sc1.1O3 formed after a FGA at 600 ºC using Ti as top electrode (in black) before (solid lines) and after a second FGA at due to the formation of additional dangling bonds, as has been reported in other works on scavenging [25,54,55]. This value is almost two orders of magnitude higher than the Pt case, which was 3×10 11 eV −1 cm −2 .…”

Thermal phase separation of ZrSiO4thin films and frequency- dependent electrical characteristics of the Al/ZrSiO4/p-Si/Al MOS capacitors

“…The lower intensities of the transmission peaks in the FTIR measurements support this discussion. The dangling bonds behave like a trapping center [32] and these centers may be dispersed within the dielectric layer. Due to the presence of these trap centers and dangling bonds, the dielectric properties of the ZrSiO 4 can be degraded.…”