Variation Analysis of CMOS Technologies Using Surface-Potential MOSFET Model, Journal of Telecommunications and Information Technology, 2009, nr 4

An analysis of the measured macroscopic withinwafer variations for threshold voltage (Vth) and on-current (Ion) over several technology generations (180 nm, 100 nm and 65 nm) is reported. It is verified that the dominant microscopic variations of the MOSFET device can be extracted quantitatively from these macroscopic variation data by applying the surface-potential compact model Hiroshima University STARC IGFET model 2 (HiSIM2), which is presently brought into industrial application. Only a small number of microscopic parameters, representing substrate doping (NSUBC), pocket-implantation doping (NSUBP), carrier-mobility degradation due to gate-interface roughness (MUESR1) and channel-length variation during the gate formation (XLD) are found sufficient to quantitatively reproduce the measured macroscopic within-wafer variations of Vth and Ion for all channel length Lg and all technology generations. Quantitative improvements from 180 nm to 65 nm are confirmed to be quite large for MUESR1 (about 70%) and Lmin(XLD) (55%) variations, related to the gate-oxide interface and the gate-stack structuring, respectively. On the other hand, doping-related technology advances, which are reflected by the variation magnitudes of NSUBC (30%) and NSUBP (25%), are found to be considerably smaller. Furthermore, specific combinations of extreme microscopic parameter-variation values are able to represent the boundaries of macroscopic fabrication inaccuracies for Vth and Ion. These combinations are found to remain identical, not only for all Lg of a given technology node, but also for all investigated technologies with minimum Lg of 180 nm, 100 nm and 65 nm

Effects of nonequilibrium atmospheric-pressure O2 plasma-assisted annealing on anatase TiO2 nanoparticles

Anatase TiO2 nanoparticles (NPs) immobilized on glass substrates were annealed with the assistance of nonequilibrium atmospheric-pressure O2 plasma. The plasma-assisted annealing greatly enhanced the photodecomposition and photobactericidal activity as compared with electric-furnace annealing. The plasma-assisted annealing reduced the TiO2 NP agglomerate size and increased the optical absorption, the photoinduced electrical conductivity, the amounts of bridging and terminal oxygen groups, and the (112)/(101) plane intensity ratio, causing the lattice oxygen deficiency that formed partially Ti-rich surface portions. The enhanced photobactericidal activity would arise from the bridging and terminal oxygen groups. The enhanced photodecomposition would arise from the increased concentration of photogenerated carriers due to the following three factors. The first is the optical absorption increased by the agglomerate size reduction and the (112) plane growth or appearance, which exert scattering more incident photons. The second is the charge separation of photogenerated carriers facilitated by the bridging and terminal oxygen groups, which originate from oxygen vacancies via oxygen ion impact from the plasma. The third is the charge transfer of plasmon-excited electrons from the partially Ti-rich portions to TiO2. The enhanced photodecomposition would also arise from more reactive oxygen species generated from the bridging and terminal oxygen groups by the photogenerated carriers

Interface-induced perpendicular magnetic anisotropy of Co nanoparticles on single-layer h-BN/Pt(111)

Ferromagnetism with perpendicular magnetic anisotropy (PMA) was observed at room temperature in cobalt nanoparticles (NPs) grown on hexagonal boron nitride (h-BN) on a Pt(111) surface. It was shown that the Co NPs have planar hexagonal shapes with a mean diameter of ∼20 nm and a mean height of ∼1.6 nm. The depth-resolved analysis of X-ray magnetic circular dichroism at the Co L2,3-edges revealed that in the ferromagnetic Co NPs, the ratio of the orbital magnetic moment to the spin magnetic moment in the out-of-plane direction becomes larger at the Co NP/h-BN interface than the ratio in bulk Co. The B and N K-edge near edge X-ray absorption fine structures showed the orbital hybridization between the π orbitals of h-BN and d orbitals of Co at the interface, as an origin of the orbital magnetic moment enhancement possibly giving rise to PMA in the Co NPs