Mechanisms and Kinetics of Misfit Dislocation Formation in Heteroepitaxial Thin Films

Nix, William D.; Noble, D. B.; Turlo, J. F.

doi:10.1557/proc-188-315

Cited by 40 publications

(12 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Then, each threading part of the dislocation moves toward the edges of the sample, leaving a misfit dislocation in the plane of the interface. The kinetics of such misfit dislocation propagation has been extensively investigated by two categorized methods; either direct observation of dislocation velocities by TEM or measurements of maximum length of dislocations by Nomarski interference microscopy of defect-etched surfaces [82][83][84][85][86]. These studies, irrespective of the difference of measurements, show reasonable quantitative agreement each other.…”

Section: Mechanism Of Strain Relaxationmentioning

confidence: 99%

Fabrication technology of SiGe hetero-structures and their properties

Shiraki

Sakai

2005

Surface Science Reports

View full text Add to dashboard Cite

Section: Mechanism Of Strain Relaxationmentioning

confidence: 99%

Fabrication technology of SiGe hetero-structures and their properties

Shiraki

Sakai

2005

Surface Science Reports

View full text Add to dashboard Cite

“…Based on an energy balance, respectively, force-balance approach, both models predict the critical layer thicknesses as well as the average dislocation densities as a function of epilayer thickness and lattice mismatch in thermodynamic equilibrium. For most practical growth conditions, however, the formation of misfit dislocations is governed by the dislocation kinetics, which are determined by nucleation of dislocation half-loops, 9,10 dislocation multiplication, 11 frictional glide forces, 9,11 as well as by pinning of dislocations at defects or at intersections with other dislocations. 12 The corresponding kinetic barriers generally lead to a retardation of the strain relaxation process and a strong increase of the critical thicknesses as compared to the predictions of the equilibrium MB and the FdM models.…”

Section: Introductionmentioning

confidence: 99%

“…͑b͒ Line profile across the(11) and ͑22͒ diffraction streaks, as indicated by the white line in ͑a͒. ͑c͒ Evolution of the line profile plotted as a function of the PbTe 0.58 Se 0.42 layer thickness.…”

mentioning

confidence: 99%

Critical thickness and strain relaxation in high-misfit heteroepitaxial systems:PbTe1−xSexon PbSe (001)

Wiesauer

Springholz

2004

Phys. Rev. B

View full text Add to dashboard Cite

Strain relaxation and misfit dislocation formation is investigated for the high-misfit PbTe 1Ϫx Se x /PbSe ͑001͒ heteroepitaxial system in which the lattice mismatch varies from 0% to 5.5%. Because a two-dimensional ͑2D͒ layer growth prevails for all PbTe 1Ϫx Se x ternary compositions, the lattice mismatch is relaxed purely by misfit dislocations. In addition, it is found that strain relaxation is not hindered by dislocation kinetics. Therefore, this material combination is an ideal model system for testing the equilibrium Frank-van der Merwe and Matthews-Blakeslee strain relaxation models. In our experiments, we find significantly lower values of the critical layer thickness as compared to the model predictions. This discrepancy is caused by the inappropriate description of the dislocation self-energies when the layer thickness becomes comparable to the dislocation core radius. To resolve this problem, a modified expression for the dislocation self-energy is proposed. The resulting theoretical critical thicknesses are in excellent agreement with the experimental data. In addition, a remarkable universal scaling behavior is found for the strain relaxation data. This underlines the breakdown of the current strain relaxation models.

show abstract

“…Specifically, when a thin epitaxial film with a lattice constant of a e is grown epitaxially on a suitable substrate of lattice constant a s , where a e = a s , the layer is grown in a state of biaxial strain. [11][12][13] Initially, the strain is accommodated elastically by the epitaxial layer and is stored as elastic-strain energy. As the thickness of the epitaxial layer is increased, the stain energy increases accordingly.…”

Section: Introductionmentioning

confidence: 99%

Threading and misfit-dislocation motion in molecular-beam epitaxy-grown HgCdTe epilayers

Carmody

Lee

Zandian

et al. 2003

Journal of Elec Materi

View full text Add to dashboard Cite

INTRODUCTIONThe performance of long-wave infrared (LWIR) and very long-wave infrared (VLWIR) photovoltaic devices can be degraded by the presence of dislocations in the HgCdTe epitaxial layer. 1-5 Dislocations threading the junction region can theoretically act as tunneling (conductive) pathways, and dislocations in the active layer can also act as trapping and recombination centers that degrade detector performance. [1][2][3][4][5] When dislocations in LWIR and VLWIR HgCdTe focal-plane arrays (FPAs) intersect the diode region, they result in degraded zero-bias impedance (R o A) and an increased diode dark current. Consequently, understanding and controlling the formation and motion of dislocations in the junction region of the diode are of critical concern when fabricating highperformance LWIR and VLWIR detectors.It is well-known that the misfit strain between the substrate and the epitaxial layer in heteroepitaxial systems is accommodated (at least partially) by the formation of misfit dislocations at the substrate/ epilayer interface. 6-10 These interfacial misfit dislocations are far from the metallurgical-junction interface and are believed to have minimal impact on diode performance. However, for a typical LWIR heterojunction-device structure, where a cap layer is grown on top of the absorber layer, misfit dislocations can theoretically form near the p-n junction at the cap/absorber interface.The formation of misfit dislocations at the interface between the substrate and the absorber layer and between the absorber layer and the cap depends on the misfit strain between the adjacent layers and the thickness of each layer. Because the location, density, and mobility of these misfit dislocations can degrade individual diode performance and, thus, Lattice mismatch between the substrate and the absorber layer in single-color HgCdTe infrared (IR) detectors and between band 1 and band 2 in two-color detectors results in the formation of crosshatch lines on the surface and an array of misfit dislocations at the epi-interfaces. Threading dislocations originating in the substrate can also bend into the interface plane and result in misfit dislocations because of the lattice mismatch. The existence of dislocations threading through the junction region of HgCdTe IR-photovoltaic detectors can greatly affect device performance. High-quality CdZnTe substrates and controlled molecular-beam epitaxy (MBE) growth of HgCdTe can result in very low threading-dislocation densities as measured by the etch-pit density (EPD ∼ 10 4 cm -2 ). However, dislocation gettering to regions of high stress (such as etched holes, voids, and implanted-junction regions) at elevated-processing temperatures can result in a high density of dislocations in the junction region that can greatly reduce detector performance. We have performed experiments to determine if the dislocations that getter to these regions of high stress are misfit dislocations at the substrate/absorber interface that have a threading component extending to the upper surface of t...

show abstract

Mechanisms and Kinetics of Misfit Dislocation Formation in Heteroepitaxial Thin Films

Cited by 40 publications

References 22 publications

Fabrication technology of SiGe hetero-structures and their properties

Fabrication technology of SiGe hetero-structures and their properties

Critical thickness and strain relaxation in high-misfit heteroepitaxial systems:PbTe1−xSexon PbSe (001)

Threading and misfit-dislocation motion in molecular-beam epitaxy-grown HgCdTe epilayers

Contact Info

Product

Resources

About