A. E. Luk’yanov

Device structures on porous silicon studied by scanning electron microscopy in the electron‐beam current mode

Contacts metal/porous silicon and p/n device structures on porous silicon were studied by scanning electron microscopy in the electron‐beam‐induced current mode. It is shown that the drift processes are dominant in operation of porous silicon‐based devices. We present the theoretical analysis of electron‐beam‐induced current measurements and estimate such important parameters of device structures as: the width of the space‐charge region (several microns), charge state density in the space‐charge region (1014–1015 cm−3), and electron drift length (up to 10−3 cm). The spatial distribution of the electric field in space‐charge region was derived. The possibility of studying the influence of porous silicon/crystalline silicon interfaces on operation of porous silicon‐based devices has been illustrated.

Analysis of formulas for calculating the main characteristics of backscattered electrons and how they compare to experimental results

Semiempirical relations for the following basic parameters of backscattered electrons in a scanning electron microscope are derived: reflection coefficient; average and most probable energies; energy spectra; and energy of backscattered electrons, depending on the angle of exit. The energy dependence is shown to have a maximum in the angular region of backscattered electrons Θ = 65°–75°.

Fianite: A multipurpose electronics material

Fianite-zirconium dioxide, stabilized by yttrium (YSZ) has a unique combination of physical and chemical properties that made it a very promising material for a wide range of applications. In this work, we consider the use of fianite as a bulk substrate and buffer layer for AIIIBV epitaxy, and as an antireflection and protective coating for photo detectors and solar cells.

Heteroepitaxial III–V films on fianite substrates and buffer layers

GaAs, GaSb, AlGaAs, and InGaAs epitaxial films and multilayer AlGaAs/InGaAs/GaAs heterostructures for PHEMT field-effect transistors have been obtained on fianite substrates by metal-organic vapour phase epitaxy. Films of different III–V compounds, including GaN, were grown on Si and GaAs substrates with a simple single buffer layer (fianite) and double buffer layer (fianite on porous Si and GaAs). It is established that the use of a two-layer buffer improves the structural quality and homogeneity of III–V films. A possibility of controlling the phase composition of GaN films using a corresponding buffer layer is shown. It is found that the use of a two-layer buffer increases the electrical homogeneity and decreases the electrical activity of defects in GaN films.

New possibilities and some artifacts of the cathodoluminescent mode in scanning electron microscopy

Lightning inside the chamber of a scanning electron microscope (SEM), caused by electrons being scattering from a sample (and parts of the chamber), is observed and analyzed. These electrons generate the luminescence in a Thornly–Everhart collector. This parasitic effect (artifact) must be considered and eliminated in all experiments with the cathodoluminescent (CL) mode of SEM. A new technique for measuring surface potential on dielectric samples is proposed. It is based on variations in the CL signal during electron irradiation of a sample in SEM.

Optimizing annular semiconductor detectors of back scattered electrons in SEM

Characteristics of a various annular detectors of back scattered electrons (BSEs) in scanning electron microscopes (SEMs) are analyzed. Modified configurations of detectors that substantially improve their efficiency are proposed (e.g., using rings with variable width and arranged perpendicular to the incident flux of BSEs).

Epitaxial films of GeSi, AlGaN, and GaSb and GaSb/InAs superlattices on substrates of fianite

Fianite is a single crystal of cubic solid solutions based on zirconium dioxide (ZrO2) or hafnium dioxide (HfO2) with stabilizing oxides of yttrium, scandium, and lanthanides. It is characterized by a unique combination of physical and chemical properties, making it a promising material for wide use in electronics. In this work, we consider new uses of fianite as a monolith substrate for obtaining Ge, GeSi, AlGaN, and GaSb epitaxial films and GaSb/InAs superlattices.

Heteroepitaxial GaN films on silicon substrates with porous buffer layers

New complex buffer layers based on a porous material have been developed for epitaxial growth of GaN films on Si substrates. The characteristics of gallium nitride heteroepitaxial layers grown on silicon substrates with new buffer layers by metal-organic vapor phase epitaxy are investigated. It is shown that the porous buffer layers improve the electric homogeneity and increase the photoluminescence intensity of epitaxial GaN films on Si substrates to the values comparable with those for reference GaN films on Al2O3 substrates. It is found that a fianite layer in a complex buffer is a barrier for silicon diffusion from the substrate into a GaN film.

A SHF-SEM method of induced current

We consider features of studying semiconductor structures by SEM with an attachment for registering microwave signal variations when a sample in an SHF field is irradiated by pulsing electronic probe.

Local transverse diffusion of light due to laguerre laser beam diffraction

When shading half of a Laguerre laser light beam with a semi-infinite metal screen with an imperfect edge the effect of fine structure formation in a transverse diffusion of “half-beam” light and its further evolution in the process of half-beam space propagation were experimentally revealed.