Strain relaxation properties of InAsyP1−y metamorphic materials grown on InP substrates

Hudait, Mantu K.; Lin, Y.; Ringel, S. A.

doi:10.1063/1.3098232

Cited by 54 publications

(39 citation statements)

References 42 publications

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“…Symmetric relaxation along two orthogonal h110i directions indicates similar total misfit dislocation length in both directions, suggesting that the relaxation is near equilibrium. Besides, as the epilayer tilt is primarily caused by nonzero net out-of-plane Burgers vectors due to imbalance between dislocation glide/multiplication in different directions, the small lattice tilt amplitude also indicates nearly equal amounts of a and b dislocation involved in the relaxation process, 23 supporting the conclusion that the InAlAs buffer relaxed symmetrically from the above analysis.…”

Section: Strain Relaxation Propertiessupporting

confidence: 69%

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Role of InAs and GaAs terminated heterointerfaces at source/channel on the mixed As-Sb staggered gap tunnel field effect transistor structures grown by molecular beam epitaxy

Zhu

Jain

Vijayaraghavan

et al. 2012

Journal of Applied Physics

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Articles you may be interested inThe structural, morphological, defect properties, and OFF state leakage current mechanism of mixed As-Sb type-II staggered gap GaAs-like and InAs-like interface heterostructure tunnel field effect transistors (TFETs) grown on InP substrates using linearly graded In x Al 1-x As buffer by molecular beam epitaxy are investigated and compared. Symmetric relaxation of >90% and >75% in the two orthogonal h110i directions with minimal lattice tilt was observed for the terminal GaAs 0.35 Sb 0.65 and In 0.7 Ga 0.3 As active layers of GaAs-like and InAs-like interface TFET structures, respectively, indicating that nearly equal numbers of a and b dislocations were formed during the relaxation process. Atomic force microscopy reveals extremely ordered crosshatch morphology and low root mean square roughness of $3.17 nm for the InAs-like interface TFET structure compared to the GaAs-like interface TFET structure of $4.46 nm at the same degree of lattice mismatch with respect to the InP substrates. The GaAs-like interface exhibited higher dislocation density, as observed by cross-sectional transmission electron microscopy, resulting in the elongation of reciprocal lattice point of In 0.7 Ga 0.3 As channel and drain layers in the reciprocal space maps, while the InAs-like interface creates a defect-free interface for the pseudomorphic growth of the In 0.7 Ga 0.3 As channel and drain layers with minimal elongation along the Dx direction. The impact of the structural differences between the two interface types on metamorphic TFET devices was demonstrated by comparing p þ -i-n þ leakage current of identical TFET devices that were fabricated using GaAs-like and InAs-like interface TFET structures. Higher OFF state leakage current dominated by band-to-band tunneling process due to higher degree of defects and dislocations was observed in GaAs-like interface compared to InAs-like interface where type-II staggered band alignment was well maintained. Significantly lower OFF state leakage current dominated by the field enhanced Shockley-Read-Hall generation-recombination process at different temperatures was observed in InAs-like TFET structure. The fixed positive charge at the source/channel heterointerface influences the band lineup substantially with charge density greater than 1 Â 10 12 /cm 2 and the band alignment is converted from staggered gap to broken gap at $6 Â 10 12 /cm 2 . Clearly, InAs-like interface TFET structure exhibited 4Â lower OFF state leakage current, which is attributed primarily to the impact of the layer roughness, defect properties on the carrier recombination rate, suggesting great promise for metamorphic TFET devices for high-performance, and ultra-low power applications. V C 2012 American Institute of Physics.

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Section: Strain Relaxation Propertiessupporting

confidence: 69%

“…In-plane lattice constant, a, and out-of-plane lattice constant, c, can be determined using Bragg's law from asymmetric and symmetric RSMs, respectively. The relaxed layer lattice constant, a r , and the strain, e, of each layer with respect to the substrate can be calculated using 23,24 …”

Section: A Structural Characterization and Strain Relaxation Propertiesmentioning

confidence: 99%

Role of InAs and GaAs terminated heterointerfaces at source/channel on the mixed As-Sb staggered gap tunnel field effect transistor structures grown by molecular beam epitaxy

Zhu

Jain

Vijayaraghavan

et al. 2012

Journal of Applied Physics

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“…When the Si (001) surface is 6°offcut, it is speculated that certain Burgers vectors are preferred at nucleation and this results in an imbalance in the Burgers vectors. [23][24][25] When the possible annihilation events are completed under the processing conditions used in this experiment, more misfit dislocations remain at the Ge/Si interface for the sample with 6°offcut that eventually thread to the top surface, hence giving rise to a higher net TDD.…”

Section: Resultsmentioning

confidence: 99%

Comparative Studies of the Growth and Characterization of Germanium Epitaxial Film on Silicon (001) with 0° and 6° Offcut

Lee

Tan

Jandl

et al. 2013

Journal of Elec Materi

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The quality of germanium (Ge) epitaxial films grown directly on silicon (Si) (001) with 0°and 6°offcut orientation using a reduced-pressure chemical vapor deposition system is studied and compared. Ge film grown on Si (001) with 6°offcut presents $65% higher threading dislocation density and higher root-mean-square (RMS) surface roughness (1.92 nm versus 0.98 nm) than Ge film grown on Si (001) with 0°offcut. Plan-view transmission electron microscopy also reveals that threading dislocations are more severe (in terms of contrast and density) for the 6°offcut. In addition, both high-resolution x-ray diffraction and Raman spectroscopy analyses show that the Ge epilayer on 6°offcut wafer presents higher tensile strain. The poorer quality of the Ge film on Si (001) with 6°offcut is a result of an imbalance in Burgers vectors that favors dislocation nucleation over annihilation.

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“…Additionally, the in-plane and out-of-plane lattice constants for each material were calculated using the asymmetric (115) and symmetric (004) RSMs respectively, and methods outlined in literature. 21 Utilizing the experimentally derived lattice constants, the relaxation state of the Ge epilayer was determined with respect to the Si substrate, indicating that the as-grown Ge-on-Si thin-film was ∼99% relaxed. Upon further inspection of the asymmetric (115) RSM (Figure 3b), the (115) Ge RLP was found to be distinctly shifted towards lower Q x , deviating from the vector (pointing towards (000) in reciprocal space) indicative of full epilayer relaxation.…”

Section: A Materials Characterizationmentioning

confidence: 99%

Growth, structural, and electrical properties of germanium-on-silicon heterostructure by molecular beam epitaxy

et al. 2017

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The growth, morphological, and electrical properties of thin-film Ge grown by molecular beam epitaxy on Si using a two-step growth process were investigated. High-resolution x-ray diffraction analysis demonstrated ∼0.10% tensile-strained Ge epilayer, owing to the thermal expansion coefficient mismatch between Ge and Si, and negligible epilayer lattice tilt. Micro-Raman spectroscopic analysis corroborated the strain-state of the Ge thin-film. Cross-sectional transmission electron microscopy revealed the formation of 90 ° Lomer dislocation network at Ge/Si heterointerface, suggesting the rapid and complete relaxation of Ge epilayer during growth. Atomic force micrographs exhibited smooth surface morphology with surface roughness < 2 nm. Temperature dependent Hall mobility measurements and the modelling thereof indicated that ionized impurity scattering limited carrier mobility in Ge layer. Capacitance- and conductance-voltage measurements were performed to determine the effect of epilayer dislocation density on interfacial defect states (Dit) and their energy distribution. Finally, extracted Dit values were benchmarked against published Dit data for Ge MOS devices, as a function of threading dislocation density within the Ge layer. The results obtained were comparable with Ge MOS devices integrated on Si via alternative buffer schemes. This comprehensive study of directly-grown epitaxial Ge-on-Si provides a pathway for the development of Ge-based electronic devices on Si.

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Strain relaxation properties of InAsyP1−y metamorphic materials grown on InP substrates

Cited by 54 publications

References 42 publications

Role of InAs and GaAs terminated heterointerfaces at source/channel on the mixed As-Sb staggered gap tunnel field effect transistor structures grown by molecular beam epitaxy

Role of InAs and GaAs terminated heterointerfaces at source/channel on the mixed As-Sb staggered gap tunnel field effect transistor structures grown by molecular beam epitaxy

Comparative Studies of the Growth and Characterization of Germanium Epitaxial Film on Silicon (001) with 0° and 6° Offcut

Growth, structural, and electrical properties of germanium-on-silicon heterostructure by molecular beam epitaxy

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