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Title: Evaluation of thickness and strain of thin planar layers of InAs on GaAs(001) using spectroscopic ellipsometry

Abstract

We develop a technique for accurately measuring thickness of planar InAs films grown on (001) GaAs by spectroscopic ellipsometry, using bulk optical constants. We observe that the critical point structure for the E{sub 1} and E{sub 1} + Δ{sub 1} transitions extracted from the measured dielectric properties varies with strain in the layer. Transmission electron microscopy confirms the extracted thickness and measures the residual strain based on the dislocation spacing in the film. At small thickness, the E{sub 1} critical point is seen to markedly deviate from the dependence predicted by deformation potential theory and appears to be consistent with additional quantum confinement effects.

Authors:
; ; ; ; ; ;  [1]
  1. Nano Electronic Materials Branch (RXAN), Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433-7707 (United States)
Publication Date:
OSTI Identifier:
22311134
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 3; Other Information: (c) 2014 U.S. Government; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; DEFORMATION; DIELECTRIC PROPERTIES; DISLOCATIONS; ELLIPSOMETRY; EVALUATION; FILMS; GALLIUM ARSENIDES; INDIUM ARSENIDES; LAYERS; STRAINS; THICKNESS; TRANSMISSION ELECTRON MICROSCOPY

Citation Formats

Eyink, K. G., Szmulowicz, F., Esposito, D., Grazulis, L., Hill, M., Mahalingam, K., and Aronow, A. J. Evaluation of thickness and strain of thin planar layers of InAs on GaAs(001) using spectroscopic ellipsometry. United States: N. p., 2014. Web. doi:10.1063/1.4890236.
Eyink, K. G., Szmulowicz, F., Esposito, D., Grazulis, L., Hill, M., Mahalingam, K., & Aronow, A. J. Evaluation of thickness and strain of thin planar layers of InAs on GaAs(001) using spectroscopic ellipsometry. United States. doi:10.1063/1.4890236.
Eyink, K. G., Szmulowicz, F., Esposito, D., Grazulis, L., Hill, M., Mahalingam, K., and Aronow, A. J. Mon . "Evaluation of thickness and strain of thin planar layers of InAs on GaAs(001) using spectroscopic ellipsometry". United States. doi:10.1063/1.4890236.
@article{osti_22311134,
title = {Evaluation of thickness and strain of thin planar layers of InAs on GaAs(001) using spectroscopic ellipsometry},
author = {Eyink, K. G. and Szmulowicz, F. and Esposito, D. and Grazulis, L. and Hill, M. and Mahalingam, K. and Aronow, A. J.},
abstractNote = {We develop a technique for accurately measuring thickness of planar InAs films grown on (001) GaAs by spectroscopic ellipsometry, using bulk optical constants. We observe that the critical point structure for the E{sub 1} and E{sub 1} + Δ{sub 1} transitions extracted from the measured dielectric properties varies with strain in the layer. Transmission electron microscopy confirms the extracted thickness and measures the residual strain based on the dislocation spacing in the film. At small thickness, the E{sub 1} critical point is seen to markedly deviate from the dependence predicted by deformation potential theory and appears to be consistent with additional quantum confinement effects.},
doi = {10.1063/1.4890236},
journal = {Applied Physics Letters},
number = 3,
volume = 105,
place = {United States},
year = {Mon Jul 21 00:00:00 EDT 2014},
month = {Mon Jul 21 00:00:00 EDT 2014}
}
  • The optical properties of In[sub [ital x]]Ga[sub 1[minus][ital x]]P/GaAs and In[sub [ital x]]Ga[sub 1[minus][ital x]]P/graded InGaP/GaP (0.25[le][ital x][le]0.8) epitaxial layers have been studied using spectroscopic ellipsometry and Raman spectroscopy. The ([ital E][sub 1],[ital E][sub 1]+[Delta][sub 1]) critical points and the first-order phonon frequencies were determined as a function of In composition. The general behavior of the peak shifts and broadenings of both the [ital E][sub 1] gaps and the optical phonons of In[sub [ital x]]Ga[sub 1[minus][ital x]]P/GaAs can be explained in terms of biaxial strain and strain relaxation caused by lattice-mismatch. The near-cancellation of [ital E][sub 1] gap change duemore » to the compensation effect between alloy composition and misfit strain is observed. As misfit strain increases, the [ital E][sub 1] gap broadens whereas the phonon line shape does not change. In strain relaxed samples of In[sub [ital x]]Ga[sub 1[minus][ital x]]P/(GaAs, graded GaP) (0.3[le][ital x][le]0.8), the [ital E][sub 1] gap linewidth shows upward bowing as a function of In composition.« less
  • The nature of InAs/GaAs short period superlattice (SPS) and In{sub x}Ga{sub l-x}As based ohmic contacts, grown by molecular-beam epitaxy, on GaAs(100) and (111)B surfaces have been investigated. The resistive nature of the contacts formed on GaAs(100), using an intermediate InAs/GaAs SPS between the metal and the substrate were found to be comparable with those obtained with an equivalent In{sub 0.33}Ga{sub 0.67}As interlayer. A model is described that accounts for the ohmic contact to the In{sub x}Ga{sub 1-x}As structure and may apply to the SPS. Unlike the GaAs(100) configurations, similar contacts to GaAs (111)B were found to differ greatly in theirmore » resistive nature; this is a likely consequence of the laminar growth mode and poor crystalline quality of InAs epilayers grown on this substrate orientation, coupled to a higher barrier at the InAs-GaAs (111)B interface. 12 refs., 5 figs.« less
  • The dynamic hysteresis scaling behavior in epitaxial Fe/GaAs(001) and Fe/InAs(001) thin films (thickness range 7.3{endash}150 Aa) has been investigated as a function of Fe film thickness in the field sweep rate range 0.005{endash}1000 kOe/s using the magneto-optic Kerr effect. The hysteresis loop area A follows the scaling relation A{proportional_to}(dH/dt){sup {alpha}}. We find two distinct dynamic regimes: the low dynamic regime in the sweep rate range 0.005{endash}250 kOe/s, and the high dynamic regime beyond 250 kOe/s. There is a marked increase in {alpha} between the low and high dynamic regimes which we attribute to the dominant reversal mechanism changing from domainmore » wall motion to nucleation. In the low dynamic regime {alpha} is a decreasing function of Fe film thickness, and this behavior is attributed to the effect of interface-induced pinning. {copyright} 2001 American Institute of Physics.« less
  • We studied the temperature dependence of the two-dimensional to three-dimensional growth transition in InAs/GaAs(001) heteroepitaxy by means of reflection high energy electron diffraction and atomic force microscopy. The observed shift of the transition to higher InAs deposition times, at temperatures above 500 deg. C, is not a change of critical thickness for islanding, which instead, is constant in the 450-560 deg. C range. Consequently, In-Ga intermixing and surface and interface strain have a negligible dependence on temperature in this range.
  • The structural and optical properties of lattice-matched InAs{sub 0.911}Sb{sub 0.089} bulk layers and strain-balanced InAs/InAs{sub 1−x}Sb{sub x} (x ∼ 0.1–0.4) superlattices grown on (100)-oriented GaSb substrates by molecular beam epitaxy are examined using X-ray diffraction, spectroscopic ellipsometry, and temperature dependent photoluminescence spectroscopy. The photoluminescence and ellipsometry measurements determine the ground state bandgap energy and the X-ray diffraction measurements determine the layer thickness and mole fraction of the structures studied. Detailed modeling of the X-ray diffraction data is employed to quantify unintentional incorporation of approximately 1% Sb into the InAs layers of the superlattices. A Kronig-Penney model of the superlattice miniband structure ismore » used to analyze the valence band offset between InAs and InAsSb, and hence the InAsSb band edge positions at each mole fraction. The resulting composition dependence of the bandgap energy and band edge positions of InAsSb are described using the bandgap bowing model; the respective low and room temperature bowing parameters for bulk InAsSb are 938 and 750 meV for the bandgap, 558 and 383 meV for the conduction band, and −380 and −367 meV for the valence band.« less