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Title: Interface roughening and defect nucleation during solid phase epitaxy regrowth of doped and intrinsic Si{sub 0.83}Ge{sub 0.17} alloys

Abstract

Metastable pseudomorphic Si{sub 0.83}Ge{sub 0.17} with thickness of 135 nm was deposited on (001) Si substrate by molecular beam epitaxy and amorphized to a depth of {approx}360 nm, using 3x10{sup 15} cm{sup -2} Ge ions at 270 keV. Samples were regrown by solid phase epitaxy in the 500-600 degree sign C temperature range. The regrowth rate was measured in situ by time resolved reflectivity, while the structure of the epilayers was investigated by transmission electron microscopy. Three regions can be distinguished in SiGe after solid phase epitaxy, independent of the annealing temperature: (1) a 20 nm defect-free layer close to the original crystal-amorphous interface, (2) a middle region with a high density of planar defects, and (3) a layer with dislocations and stacking faults extending up to the surface. The activation energy of the SiGe solid phase epitaxy is equal to the activation energy of Si except in the middle region. The amorphous-crystal interface evolution was studied by transmission electron microscopy of partially regrown samples. In order to study the effects of dopants, some samples were also implanted with B{sup +} and Sb{sup +} ions. At the ion projected range (125 nm for both implants) the regrowth rate increases bymore » a factor of 3 with respect to the unimplanted SiGe, but the defect-free layer again is found to be about 20 nm in all cases. Moreover, the activation energy of the solid phase epitaxy regrowth process does not depend on dopant introduction, while the only observable effect of B or Sb incorporation is a smoothness of the amorphous-crystal interface during solid phase epitaxy.« less

Authors:
; ; ; ; ;  [1];  [2]
  1. MATIS CNR-INFM and Dipartimento di Fisica e Astronomia, Universita di Catania, Via S. Sofia 64, 95123 Catania (Italy)
  2. (Italy)
Publication Date:
OSTI Identifier:
20982885
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 101; Journal Issue: 10; Other Information: DOI: 10.1063/1.2732680; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ACTIVATION ENERGY; ANNEALING; ANTIMONY IONS; BINARY ALLOY SYSTEMS; BORON IONS; CRYSTAL GROWTH; DISLOCATIONS; DOPED MATERIALS; GERMANIUM ALLOYS; GERMANIUM IONS; GERMANIUM SILICIDES; MOLECULAR BEAM EPITAXY; NUCLEATION; SEMICONDUCTOR MATERIALS; SILICON ALLOYS; STACKING FAULTS; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0400-1000 K; TRANSMISSION ELECTRON MICROSCOPY

Citation Formats

D'Angelo, D., Piro, A. M., Terrasi, A., Grimaldi, M. G., Mirabella, S., Bongiorno, C., and CNR-IMM, Sezione di Catania, Stradale Primosole 50, 95121 Catania. Interface roughening and defect nucleation during solid phase epitaxy regrowth of doped and intrinsic Si{sub 0.83}Ge{sub 0.17} alloys. United States: N. p., 2007. Web. doi:10.1063/1.2732680.
D'Angelo, D., Piro, A. M., Terrasi, A., Grimaldi, M. G., Mirabella, S., Bongiorno, C., & CNR-IMM, Sezione di Catania, Stradale Primosole 50, 95121 Catania. Interface roughening and defect nucleation during solid phase epitaxy regrowth of doped and intrinsic Si{sub 0.83}Ge{sub 0.17} alloys. United States. doi:10.1063/1.2732680.
D'Angelo, D., Piro, A. M., Terrasi, A., Grimaldi, M. G., Mirabella, S., Bongiorno, C., and CNR-IMM, Sezione di Catania, Stradale Primosole 50, 95121 Catania. Tue . "Interface roughening and defect nucleation during solid phase epitaxy regrowth of doped and intrinsic Si{sub 0.83}Ge{sub 0.17} alloys". United States. doi:10.1063/1.2732680.
@article{osti_20982885,
title = {Interface roughening and defect nucleation during solid phase epitaxy regrowth of doped and intrinsic Si{sub 0.83}Ge{sub 0.17} alloys},
author = {D'Angelo, D. and Piro, A. M. and Terrasi, A. and Grimaldi, M. G. and Mirabella, S. and Bongiorno, C. and CNR-IMM, Sezione di Catania, Stradale Primosole 50, 95121 Catania},
abstractNote = {Metastable pseudomorphic Si{sub 0.83}Ge{sub 0.17} with thickness of 135 nm was deposited on (001) Si substrate by molecular beam epitaxy and amorphized to a depth of {approx}360 nm, using 3x10{sup 15} cm{sup -2} Ge ions at 270 keV. Samples were regrown by solid phase epitaxy in the 500-600 degree sign C temperature range. The regrowth rate was measured in situ by time resolved reflectivity, while the structure of the epilayers was investigated by transmission electron microscopy. Three regions can be distinguished in SiGe after solid phase epitaxy, independent of the annealing temperature: (1) a 20 nm defect-free layer close to the original crystal-amorphous interface, (2) a middle region with a high density of planar defects, and (3) a layer with dislocations and stacking faults extending up to the surface. The activation energy of the SiGe solid phase epitaxy is equal to the activation energy of Si except in the middle region. The amorphous-crystal interface evolution was studied by transmission electron microscopy of partially regrown samples. In order to study the effects of dopants, some samples were also implanted with B{sup +} and Sb{sup +} ions. At the ion projected range (125 nm for both implants) the regrowth rate increases by a factor of 3 with respect to the unimplanted SiGe, but the defect-free layer again is found to be about 20 nm in all cases. Moreover, the activation energy of the solid phase epitaxy regrowth process does not depend on dopant introduction, while the only observable effect of B or Sb incorporation is a smoothness of the amorphous-crystal interface during solid phase epitaxy.},
doi = {10.1063/1.2732680},
journal = {Journal of Applied Physics},
number = 10,
volume = 101,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • We have measured the diamagnetic shift of band-edge luminescence, no-phonon peak, and phonon sideband from a pseudomorphic, undoped Si{sub 0.83}Ge{sub 0.17}/Si quantum well using high-field magnetoluminescence spectroscopy. The quadratic dependence of the diamagnetic shift of the no-phonon luminescence peak suggests that the luminescence originates from excitons. Using a variational calculation, we determine the effective heavy-hole mass and the exciton binding energy to be 0.27{ital m}{sub 0} and 14.8 meV, respectively, and compare these results with reported values obtained from other measurement techniques. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.
  • This work reports on the detailed plasma-assisted molecular beam epitaxy (PAMBE) growth of ultra-thin In{sub 0.17}Al{sub 0.83}N/GaN heterostructures on Si(111) substrate with three different buffer thickness (600 nm, 400 nm, and 200 nm). Growth through critical optimization of growth conditions is followed by the investigation of impact of varying buffer thickness on the formation of ultra-thin 1.5 nm, In{sub 0.17}Al{sub 0.83}N–1.25 nm, GaN–1.5 nm, In{sub 0.17}Al{sub 0.83}N heterostructure, in terms of threading dislocation (TD) density. Analysis reveals a drastic reduction of TD density from the order 10{sup 10 }cm{sup −2} to 10{sup 8 }cm{sup −2} with increasing buffer thickness resulting smooth ultra-thin active region for thick buffer structure.more » Increasing strain with decreasing buffer thickness is studied through reciprocal space mapping analysis. Surface morphology through atomic force microscopy analysis also supports our study by observing an increase of pits and root mean square value (0.89 nm, 1.2 nm, and 1.45 nm) with decreasing buffer thickness which are resulted due to the internal strain and TDs.« less
  • Time-resolved reflectivity has been used to measure the rate of solid phase epitaxial regrowth (SPER) [ital in] [ital situ] during annealing of strained Si[sub 0.88]Ge[sub 0.12] epilayers on Si preamorphized by the implantation of Si. The SPER velocities were measured over more than two orders of magnitude at temperatures from 503 to 603 [degree]C. The results confirm that the average SPER velocity in thin, strained Si[sub 0.88]Ge[sub 0.12] layers is less than that in pure Si. Furthermore, these real-time measurements demonstrate that the SPER rate for strained Si[sub 0.88]Ge[sub 0.12] alloys is not a constant during regrowth at a fixedmore » temperature but varies systematically as a function of the position of the amorphous-crystalline interface. The activation energy barrier of SPER in strained Si[sub 0.88]Ge[sub 0.12] is higher than that in pure Si and is also a function of interface position, ranging from 2.94 to 3.11 eV. Cross-section transmission electron microscopy shows that strain-relieving defects are introduced coincidentally with the minimum regrowth rate.« less
  • The valence band offset, {Delta}E{sub V}, at an Al{sub 2}O{sub 3}/In{sub 0.17}Al{sub 0.83}N interface formed by atomic layer deposition was measured by x-ray photoelectron spectroscopy. The conventional method of using the core level separation, {Delta}E{sub CL}, between O 1s and In 4d resulted in {Delta}E{sub V} = 1.3 eV, which was apparently consistent with the direct observation of the valence band edge varying the photoelectron exit angle, {theta}. However, {Delta}E{sub CL} and full width at half maximum of core-level spectra were dependent on {theta}, which indicated significant potential gradients in Al{sub 2}O{sub 3} and InAlN layers. An actual {Delta}E{sub V}more » of 1.2 eV was obtained considering the potential gradients.« less
  • The effect of room temperature sulfur passivation of the surface of Ge{sub 0.83}Sn{sub 0.17} prior to high-k dielectric (HfO{sub 2}) deposition is investigated. X-ray photoelectron spectroscopy (XPS) was used to examine the chemical bonding at the interface of HfO{sub 2} and Ge{sub 0.83}Sn{sub 0.17}. Sulfur passivation is found to be effective in suppressing the formation of both Ge oxides and Sn oxides. A comparison of XPS results for sulfur-passivated and non-passivated Ge{sub 0.83}Sn{sub 0.17} samples shows that sulfur passivation of the GeSn surface could also suppress the surface segregation of Sn atoms. In addition, sulfur passivation reduces the interface trapmore » density D{sub it} at the high-k dielectric/Ge{sub 0.83}Sn{sub 0.17} interface from the valence band edge to the midgap of Ge{sub 0.83}Sn{sub 0.17}, as compared with a non-passivated control. The impact of the improved D{sub it} is demonstrated in Ge{sub 0.83}Sn{sub 0.17} p-channel metal-oxide-semiconductor field-effect transistors (p-MOSFETs). Ge{sub 0.83}Sn{sub 0.17} p-MOSFETs with sulfur passivation show improved subthreshold swing S, intrinsic transconductance G{sub m,int}, and effective hole mobility μ{sub eff} as compared with the non-passivated control. At a high inversion carrier density N{sub inv} of 1 × 10{sup 13 }cm{sup −2}, sulfur passivation increases μ{sub eff} by 25% in Ge{sub 0.83}Sn{sub 0.17} p-MOSFETs.« less