Numerical calculations were used to assess the probable microscopic distribution of the electric field along or close to the actual Si-5102 interface of a metal oxide semiconductor (MOS) capacitor biased into accumulation. Silicon wafers were oxidized to 20 nm at 1150°C by rapid thermal oxidation, according to two different thermal recipes in order to yield different Si-5i02 interface roughnesses. After oxide removal, typical atomic force microscopy (AFM) line scans of the silicon surface were exported into the MEDICI program as a description of the Si-5i02 interface in order to calculate the electric field distribution within the oxide layer of a bidimensional MOS capacitor biased into accumulation. This distribution was found to be highly inhomogeneous even for relatively smooth Si-5i02 interfaces, displaying strong local electric field enhancements, the spatial distribution of which will be called electronic roughness in this work. Simple local oxide thinning at the position of the protrusions cannot account for these field enhancements, thus indicating that the shape of the protrusion is dictating the electronic roughness. The electronic roughness could be correlated with electric breakdown characteristics of actual MOS capacitors prepared on these wafers. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Ebd (MV/cm) ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 134.129.182.74 Downloaded on 2015-06-25 to IP
The influence of the microscopic shape anisotropy of the micelles on the pitch of a cholesteric lyotropic liquid crystal is investigated by x-ray diffraction and optical techniques. The mixture studied is potassium laurate, decanol, water, and brucine sulfate. The relative molar concentra-
The influence of two different thermal annealing cycles on the microroughness of the Si-SiO, interface and on the electrical characteristics of the Si-SiO, system has been investigated. Experiments were performed growing oxides by rapid thermal oxidation @TO) and post-oxidation annealing in N , using a slow cooling ramp recipe (SCRR) or a conventional pulsed thermal annealing recipe (PTAR). Compared to PTAR, SCRR yielded a more severe annealing in N , and slower temperature decay after MO. The thickness of the as-grown oxides was measured by ellipsometry in the whole wafer area. Laser light scattering (us) at a grazing angle and atomic force microscopy (AFM) have been used for measuring the Si-SiO, interface topography after the Si O, removal. LLS was mainly used for large-area scans (micrometric resolution) and AFM for smaii-size areas (atomic 'resolution). The results showed that oxides prepared with SCRR exhibited a smoother Si-SiO, interface at the nanometric scale and protrusions up to 2.5 nm high and up to 100 nm wide ('large protrusions') at a submicrometre scale. On the other hand, the oxides prepared with PTAR resulted in an Si-SiO, interface with protrusions up to 2 nm high and up to 5 nm wide ('sharp protrusions') at the nanometric scale and broad localized regions, sparsely distributed over the wafer area, with high root mean square (RMS) microroughness. By measuring the electrical parameters of a large number of MOS capacitors made with these oxides, we demonstrated evident experimental correlation of the electric breakdown fieid (Ebd), charge to breakdown (Qbd), Si-SiO, interface state density (D,J and AI-SiO, potential barrier height (q40) with surface microroughness and therefore with the thermal annealing cycle in N,. The oxides prepared by SCRR exhibited improved overall electrical parameters as compared to the oxides prepared
The effect of Si/SiO2 interface roughness on SiO2 breakdown characteristics is investigated by means of numerical calculations. It is shown that similar roughness values of the Si/SiO2 interface may yield different breakdown distributions. It is aL~.o shown that severe field enhancement effects may occur at the Si/SiO2 interface for some specific Si/SiO2 interface asperities. A possible correlation between Si/SiO2 interface roughness, oxygen precipitates, and breakdown characteristics is addressed.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 150.135.239.97 Downloaded on 2015-05-31 to IP
Better luminescent properties were observed on the films with the standard powder ZnGa204 x-ray diffraction pattern. Also, the substarte temperature above 500~ leads to the films with the standard powder ZnGa204 x-ray diffraction pattern. The effect of the strength of the ligand field on the resulting energy levels, labeled by their spectroscopic terms 4A2, 4T1, 4T2, and 2E. The main transition between the excited state (4T2) and luminescent center (~A2) is 2.64 eV of blue light emission (470 nm). Uniform ZnGa20~ phosphor films deposited by magnetron sputtering at proper pressure and power are obtained. Good luminescent characteristics of low voltage cathodoluminescence phosphor films are observed in this research.
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