Low-Temperature Silicon Oxidation with Very Small Activation Energy and High-Quality Interface by Electron Cyclotron Resonance Plasma Stream Irradiation
Abstract:Oxidation using electron cyclotron resonance (ECR) plasma stream provides a large silicon dioxide growth rate at the initial growth stage (>6 nm/min), a very small activation energy of 0.02 eV for oxidation, and a high-quality interface with interface trap density of 3×1010 cm-2·eV-1. The plasma stream was extracted by a divergent magnetic field from the ECR region and irradiated on a single-crystalline silicon substrate with ion energies of 10–30 eV. The high-quality interface was obtained by oxidation wit… Show more
“…Recently, unusually small activation energy values (of e.g. 0.13 eV [25] or even lower [26]) were observed for the oxidation procedure where the oxygen diffusion limit was lifted by using atomic oxygen for Si oxidation.Fig. 4Silicon oxide formation on Pd surface.…”
The effect of silicon oxide surface segregation on the locally-resolved kinetics of the CO oxidation reaction on individual grains of a polycrystalline Pd foil was studied in situ by PEEM, MS and XPS. The silicon oxide formation induced by Si-impurity segregation at oxidizing conditions, was monitored by XPS and its impact on the global and local (spatially resolved) kinetics of the CO oxidation was determined by MS and PEEM. The results reveal a drastic inhibiting effect of silicon oxide on the Pd reactivity towards CO oxidation, manifested both in the collapse of the global CO2 formation rate and in the modified local reactive properties of individual Pd micrograins. The presence of adsorbed oxygen on the Pd surface effectively enhances the silicon segregation to the Pd surface.Graphical Abstract
“…Recently, unusually small activation energy values (of e.g. 0.13 eV [25] or even lower [26]) were observed for the oxidation procedure where the oxygen diffusion limit was lifted by using atomic oxygen for Si oxidation.Fig. 4Silicon oxide formation on Pd surface.…”
The effect of silicon oxide surface segregation on the locally-resolved kinetics of the CO oxidation reaction on individual grains of a polycrystalline Pd foil was studied in situ by PEEM, MS and XPS. The silicon oxide formation induced by Si-impurity segregation at oxidizing conditions, was monitored by XPS and its impact on the global and local (spatially resolved) kinetics of the CO oxidation was determined by MS and PEEM. The results reveal a drastic inhibiting effect of silicon oxide on the Pd reactivity towards CO oxidation, manifested both in the collapse of the global CO2 formation rate and in the modified local reactive properties of individual Pd micrograins. The presence of adsorbed oxygen on the Pd surface effectively enhances the silicon segregation to the Pd surface.Graphical Abstract
“…Further reduction in D it can be expected by annealing the sample in 100%-H 2 ambient as reported for the SiO 2 /Si system. 12) …”
Section: Resultsmentioning
confidence: 99%
“…Recently, NTT's group has been reporting very successful results on the application of ECR to form an insulator/semiconductor interface. [10][11][12] Saito et al 12) have demonstrated that the SiO 2 /Si interface prepared by ECR plasma irradiation exhibits a very low D it of 3 Â 10 10 cm À2 ÁeV À1 . This paper describes the electrical properties of a GeO x / Ge interface prepared by irradiating an oxygen plasma stream generated by ECR directly on a Ge substrate surface.…”
We have found excellent electrical characteristics in germanium oxide grown by plasma oxidation for germanium metalinsulator-semiconductor gate dielectric applications. An oxygen plasma stream generated by electron cyclotron resonance was used to oxidize a germanium surface without substrate heating. A transmission electron microscope observation revealed that the obtained germanium oxide/germanium interface is atomically smooth. The energy distribution of interface trap density (D it ) in the upper half of the p-type germanium band gap was measured by the ac conductance method. It is shown that the D it at the midgap is $6 Â 10 10 cm À2 ÁeV À1 and increases exponentially as the energy increases to the conduction-band edge.
“…Thus the thermal activation energy for this process is very close to zero. Similar results have been reported by Kunio[22]. For thin oxides one would expect oxidation reaction to be the rate controlling step.…”
supporting
confidence: 89%
“…Oxidation rate decreased slightly for temperatures below 350 o C (Figure 2 Growth studies and electrical properties were studied by Kunio et al . Oxide was grown with a 2.45 GHz microwave source and a 500 W divergent magnetic field ECR plasma [22].…”
According to Moore's Law, which has been true so far, transistors density on a chip area doubles every two years. This increase in number of transistors requires reduced device dimensions or to say scaling by a factor of ~0.7. As the device dimensions are shrinking, high temperature processes used in CMOS device fabrication, e.g. thermal oxidation of silicon to grow gate oxide, are becoming incompatible with CMOS processing. High temperature processes could change the impurity profile in Si, produce stresses on Si wafer, and also result in high thermal budget. In the past, many attempts have been made to reduce
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