Contrast mechanism due to interface trapped charges for a buried SiO2 microstructure in scanning electron microscopy

Abstract

We clarify the scanning electron microscopic contrast mechanism for imaging a buried SiO(2) trench microstructure with interface trapped charges by simulating both electron scattering and transport. Here, the interface trapped charges make the SiO(2) film more negatively charged and increase excess holes in the space charge distribution of the electron scattering region. The generated positive surface electric field thus redistributes some emitted secondary electrons and results in the dark contrast. This contrast mechanism is validated by comparing with experiments, and it may also provide an interesting approach for imaging and detecting deep interface trapped charges in insulating films.

Versatile Growth of Freestanding Orthorhombic α-Molybdenum Trioxide Nano- and Microstructures by Rapid Thermal Processing for Gas Nanosensors

“…In this regard, Zhang et al proposed that charges in the underlying structure have influence on the secondary electron (SE) distribution in the top layer . These charges eventually lower the electron density at the overlap, resulting in a lower SE yield, which leads to the observed contrast . Such observations can have a great impact on future applications of these nano- and microribbons of α-MoO 3 .…”

The surface potential of insulating thin films negatively charged by a low-energy focused electron beam

“…4(b), the image brightness of the insulating thin film with the grounded Si substrate has a minimum value at the beam energy between 2 and 3 keV. More importantly, the lower image brightness was caused by the more negative surface potential that might make more SEs redistributed at the surface (Zhang et al, 2003(Zhang et al, , 2009.…”

Self-consistent drift-diffusion-reaction model for the electron beam interaction with dielectric samples

“…junctions). Some parts of the DDR model have already been applied to the SEM problem 13,[22][23][24]38,39 . However, these previous studies have omitted the trapping rate equations thereby missing an important feature of the charging dynamics.…”

“…In our approach, a set of equations is employed for the recombination and trapping rates, whereas, previous DDR studies 13,[22][23][24]38,39 simply use fixed values for these rates. We show that the trapping of particles introduces a large-scale (slow) dynamics into the picture and determines not only the main features of the charge density distribution inside the sample, but also the abrupt changes in the surface charge density prior to the establishment of the steady state.…”