Growth of Lattice-Matched ZnSe-ZnS Strained-Layer Superlattices Onto GaAs as An Alternative to ZnSSe Alloys

1989 ◽  
Vol 161 ◽  
Author(s):  
H. Oniyama ◽  
S. Yamaga ◽  
A. Yoshikawa
Keyword(s):  
Electron Beam ◽  
Wide Bandgap ◽  
Misfit Dislocations ◽  
Induced Current ◽  
Strained Layer ◽  
Gaas Substrates ◽  
Strained Layer Superlattice ◽  
Electron Beam Induced Current ◽  
Strained Layer Superlattices ◽  
Lattice Matched

ABSTRACTThis paper describes the results of the first attempt to reduce misfit dislocations in epilayers of a wide bandgap II-VI semiconductor on GaAs substrates by utilizing the ZnSe-ZnS strained-layer superlattice (SLS) structure. From a theoretical calculation, SLSs consisting of a 200A-ZnSe and a IOA-ZnS layer in one period can be grown as lattice-matched films to GaAs substrates. It has been found from the photoluminescence measurements and electron-beam-induced-current (EBIC) image observations that the generation of misfit dislocations can be markedly reduced, as expected.

Electron-Beam-Induced Current Observation of Misfit Dislocations at Si1-XGeX/Si Interfaces

1987 ◽  
Vol 26 (Part 2, No. 12) ◽  
pp. L1944-L1946 ◽  
Author(s):  
Yoshitaka Kohama ◽  
Yoshio Watanabe ◽  
Yukio Fukuda
Keyword(s):  
Electron Beam ◽  
Misfit Dislocations ◽  
Induced Current ◽  
Current Observation ◽  
Electron Beam Induced Current

Modification of Recombination Activity of Dislocations in Si and SiGe by Contamination and Hydrogenation

1995 ◽  
Vol 378 ◽  
Author(s):  
M. Kittler ◽  
W. Seifert ◽  
V. Higgs
Keyword(s):  
Electron Beam ◽  
Low Temperature ◽  
Electrical Activity ◽  
Misfit Dislocations ◽  
Induced Current ◽  
Temperature Dependent ◽  
Recombination Activity ◽  
Dislocation Activity ◽  
Cu Contamination ◽  
Electron Beam Induced Current

AbstractTemperature-dependent (80 … 300 K) measurements of dislocation recombination activity by the electron-beam-induced-current (EBIC) technique are reported. Controlled Cu contamination (ppb to ppm range), chemomechanical polishing and hydrogenation treatments were applied to alter dislocation properties. Increasing Cu level is found not only to increase the electrical activity of misfit dislocations in SiGe/Si structures at 300 K, but also to change its dependence on temperature. At low contamination, shallow centres control dislocation activity while deep centres are characteristic at higher Cu levels. Heavy Cu contamination results in very strong recombination activity which is attributed to precipitates. Chemomechanical polishing has an effect which is analogous to medium Cu contamination. Hydrogenation was found to passivate recombination activity at 300 K, but did not show pronounced effects on activity at low temperature.

Electron-Beam-Induced-Current (EBIC) Imaging of Defects in Si1−xGeX Multilayer Structures

1989 ◽  
Vol 148 ◽  
Author(s):  
J.C. Sturm ◽  
X. Xiao ◽  
P.M. Garone ◽  
P.V. Schwartz
Keyword(s):  
Electron Beam ◽  
Misfit Dislocations ◽  
Induced Current ◽  
High Quality ◽  
Strained Si ◽  
Density Of Dislocations ◽  
Interface Defects ◽  
Line Defects ◽  
Electron Beam Induced Current ◽  
Reaction Processing

ABSTRACTThe electron-beam-induced-current (EBIC) technique has been used to image dislocations and other defects at strained Si: Sil−xGex epitaxial interfaces and in overlying epitaxial layers grown by Limited Reaction Processing. Depending upon the bias conditions and test structure, one can distinguish between interface defects and those in overlying films. We have found that for a low density of misfit dislocations, a high quality (defect-free) overlying epitaxial layer can be grown, but for a high density of dislocations certain line defects propagate upwards in the overlying layers.

The limits of strain and lattice parameter measurements by CBED

1989 ◽  
Vol 47 ◽  
pp. 518-519
Author(s):  
Hamish L. Fraser
Keyword(s):  
Electron Beam ◽  
Mirror Symmetry ◽  
Local Symmetry ◽  
Lattice Parameter ◽  
Growth Direction ◽  
Surface Relaxation ◽  
Strained Layer ◽  
Axis Parallel ◽  
Local Lattice ◽  
Strained Layer Superlattice

The topic of strain and lattice parameter measurements using CBED is discussed by reference to several examples. In this paper, only one of these examples is referenced because of the limitation of length. In this technique, scattering in the higher order Laue zones is used to determine local lattice parameters. Work (e.g. 1) has concentrated on a model strained-layer superlattice, namely Si/Gex-Si1-x. In bulk samples, the strain is expected to be tetragonal in nature with the unique axis parallel to [100], the growth direction. When CBED patterns are recorded from the alloy epi-layers, the symmetries exhibited by the patterns are not tetragonal, but are in fact distorted from this to lower symmetries. The spatial variation of the distortion close to a strained-layer interface has been assessed. This is most readily noted by consideration of Fig. 1(a-c), which show enlargements of CBED patterns for various locations and compositions of Ge. Thus, Fig. 1(a) was obtained with the electron beam positioned in the center of a 5Ge epilayer and the distortion is consistent with an orthorhombic distortion. When the beam is situated at about 150 nm from the interface, the same part of the CBED pattern is shown in Fig. 1(b); clearly, the symmetry exhibited by the mirror planes in Fig. 1 is broken. Finally, when the electron beam is positioned in the center of a 10Ge epilayer, the CBED pattern yields the result shown in Fig. 1(c). In this case, the break in the mirror symmetry is independent of distance form the heterointerface, as might be expected from the increase in the mismatch between 5 and 10%Ge, i.e. 0.2 to 0.4%, respectively. From computer simulation, Fig.2, the apparent monocline distortion corresponding to the 5Ge epilayer is quantified as a100 = 0.5443 nm, a010 = 0.5429 nm and a001 = 0.5440 nm (all ± 0.0001 nm), and α = β = 90°, γ = 89.96 ± 0.02°. These local symmetry changes are most likely due to surface relaxation phenomena.

Electron beam induced current study of thin silicon layers on insulator substrate

1990 ◽  
Vol 48 (4) ◽  
pp. 618-619
Author(s):  
A. Buczkowski ◽  
Z. J. Radzimski ◽  
J. C. Russ ◽  
G. A. Rozgonyi
Keyword(s):  
Electron Beam ◽  
Energy Loss ◽  
Beam Energy ◽  
Collection Efficiency ◽  
Silicon Layer ◽  
Depletion Layer ◽  
Incident Electron Energy ◽  
Induced Current ◽  
Electron Hole ◽  
Electron Beam Induced Current

If a thickness of a semiconductor is smaller than the penetration depth of the electron beam, e.g. in silicon on insulator (SOI) structures, only a small portion of incident electrons energy , which is lost in a superficial silicon layer separated by the oxide from the substrate, contributes to the electron beam induced current (EBIC). Because the energy loss distribution of primary beam is not uniform and varies with beam energy, it is not straightforward to predict the optimum conditions for using this technique. Moreover, the energy losses in an ohmic or Schottky contact complicate this prediction. None of the existing theories, which are based on an assumption of a point-like region of electron beam generation, can be used satisfactorily on SOI structures. We have used a Monte Carlo technique which provide a simulation of the electron beam interactions with thin multilayer structures. The EBIC current was calculated using a simple one dimensional geometry, i.e. depletion layer separating electron- hole pairs spreads out to infinity in x- and y-direction. A point-type generation function with location being an actual location of an incident electron energy loss event has been assumed. A collection efficiency of electron-hole pairs was assumed to be 100% for carriers generated within the depletion layer, and inversely proportional to the exponential function of depth with the effective diffusion length as a parameter outside this layer. A series of simulations were performed for various thicknesses of superficial silicon layer. The geometries used for simulations were chosen to match the "real" samples used in the experimental part of this work. The theoretical data presented in Fig. 1 show how significandy the gain decreases with a decrease in superficial layer thickness in comparison with bulk material. Moreover, there is an optimum beam energy at which the gain reaches its maximum value for particular silicon thickness.

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