Characterization of Local Current Leakage in La₂O₃–Al₂O₃ Composite Films by Conductive Atomic Force Microscopy

Abstract

We show the existence of a new class of astrophysical objects where the self-gravity of the dust is balanced by the force arising from shielded electric fields on the charged dust. The problem of equilibrium dust clouds is formulated in terms of an equation of hydrostatic force balance together with an equation of state. Because of the dust charge reduction at high dust density, the adiabatic index reduces from two to zero. This gives rise to a mass limit M AS for the maximum dust mass that can be supported against gravitational collapse by these fields. If the total mass M D of the dust in the interstellar cloud exceeds M AS , the dust collapses, while in the case M D < M AS , equilibrium may be achieved. The physics of the mass limit is similar to the Chandrasekhar's mass limit for compact objects, such as white dwarfs and neutron stars.

Electronic trap characterization of the Sc2O3∕La2O3 high-κ gate stack by scanning tunneling microscopy

“…These defect mechanisms have also been observed by Seko et al in La 2 O 3 -Al 2 O 3 composite films using conductive atomic force microscopy in ambient. 9 The Sc 2 O 3 / La 2 O 3 / SiO x gate stack was formed on a n-Si substrate by electron-beam vapor deposition in UHV. The gate stack was subjected to postdeposition annealing at 300°C in nitrogen for 5 min.…”

Analysis of Local Leakage Current of Pr-Oxide Thin Films with Conductive Atomic Force Microscopy

“…For microscopic observation, current and topographic images with a scanning area of 1 m 2 were obtained by using C-AFM with a Pt-coated Si conductive tip. In order to estimate the current density from current image, a contact area of 210 -12 cm 2 for an effective C-AFM tip was employed [8] . Current leakage properties were measured under the accumulation condition.…”

Behavior of Local Charge-Trapping Sites in La2O3–Al2O3 Composite Films under Constant Voltage Stress

“…The current density was obtained by employing an effective C-AFM tip with a contact area of 2 Â 10 À12 cm 2 . 10,17) All current leakage properties were measured under the accumulation condition, in which a Si substrate becomes a cathode electrode.…”

“…under constant voltage stress Figure 1 shows current images of the same area in the PDA sample when repeating C-AFM observation at a constant substrate voltage of À3:00 V. 17) In this case, the electrical stress is applied for approximately 0.12 s per pixel (15.3 nm 2 ) of the image during one scan. Several current-leakage spots, which have a larger leakage current than that in other areas (hereafter called the background) appear in each current image.…”

“…16) Recently, we have analyzed local leakage current in such PDA-treated La 2 O 3 -Al 2 O 3 composite films by C-AFM. 17) Several leakage spots were observed in the current images of the PDA-treated films without electrical stress, and the origins of these leakage spots were categorized into at least three types. Furthermore, the differences in degradation phenomena, which depend on electrical stress conditions, were clarified.…”