Dislocations and the piezoelectric effect in III-V crystals

Booyens, H.; Vermaak, J. S.; Proto, G. R.

doi:10.1063/1.324118

Cited by 31 publications

(5 citation statements)

References 14 publications

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“…In semiconductors without inversion symmetry, e.g., III-V or II-VI compounds, the piezoelectric potential associated with the dislocations also reduces the electron mobility. 28 Previous studies of Ͼ1-m-thick InSb films have shown that the maximum electron mobility occurs close to room temperature, and the mobility decreases as the temperature is lowered. 2,5,29 Parker et al found that InSb films with a doping slab at the film/substrate interface had more than a factor of 2 lower mobility for the same carrier concentration than the films where the slab was inserted at ϳ0.75 m from the interface.…”

Section: Introductionmentioning

confidence: 97%

Evolution of structural and electronic properties of highly mismatched InSb films

Weng

Goldman

Partin

et al. 2000

Journal of Applied Physics

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N-type conductivity and properties of carbon-doped InN(0001) films grown by molecular beam epitaxy J. Appl. Phys. 113, 033501 (2013); 10.1063/1.4775736 Improved electron mobility in InSb epilayers and quantum wells on off-axis Ge (001) substrates J. Appl. Phys. 111, 073525 (2012); 10.1063/1.3702820 Effect of dislocations on electrical and electron transport properties of InN thin films. I. Strain relief and formation of a dislocation networkWe have investigated the evolution of structural and electronic properties of highly mismatched InSb films, with thicknesses ranging from 0.1 to 1.5 m. Atomic force microscopy, cross-sectional transmission electron microscopy, and high-resolution x-ray diffraction show that the 0.1 m films are nearly fully relaxed and consist of partially coalesced islands, which apparently contain threading dislocations at their boundaries. As the film thickness increases beyond 0.2 m, the island coalescence is complete and the residual strain is reduced. Although the epilayers have relaxed equally in the ͗110͘ in-plane directions, the epilayer rotation about an in-plane axis ͑epilayer tilt͒ is not equal in both ͗110͘ in-plane directions. Interestingly, the island-like surface features tend to be preferentially elongated along the axis of epilayer tilt. Furthermore, epilayer tilt which increases the substrate offcut ͑reverse tilt͒ is evident in the ͓110͔ direction. High-resolution transmission electron microscopy indicates that both pure-edge and 60°misfit dislocations contribute to the relaxation of strain. In addition, as the film thickness increases, the threading dislocation density decreases, while the corresponding room-temperature electron mobility increases. The other structural features, including the residual strain, and the surface and interface roughness, do not appear to impact the electron mobility in these InSb films. Together, these results suggest that free-carrier scattering from the threading dislocations is the primary room-temperature mobility-limiting mechanism in highly mismatched InSb films. Finally, we show quantitatively that free-carrier scattering from the lattice dilation associated with threading dislocations, rather than scattering from a depletion potential surrounding the dislocations, is the dominant factor limiting the electron mobility.

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Section: Introductionmentioning

confidence: 97%

Evolution of structural and electronic properties of highly mismatched InSb films

Weng

Goldman

Partin

et al. 2000

Journal of Applied Physics

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“…This situation differs from that encountered for representative 60°d islocations in cubic zincblende materials. 12 For an edge dislocation with Burgers vector b e , the corresponding displacement distribution is 7…”

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confidence: 99%

Piezoelectric polarization associated with dislocations in wurtzite GaN

Shi

Asbeck

1999

Applied Physics Letters

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The piezoelectric polarization and its associated charge density are calculated for edge, screw, and mixed dislocations oriented parallel to the c axis in wurtzite GaN. It is shown that the polarization field generated by screw components of dislocations is divergence free, and thus does not generate electric fields. Edge dislocations produce polarization fields that have nonzero divergence only at interfaces. These characteristics minimize the electrical and optical effects of the dislocations mediated by the piezoelectric effect.

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“…That dislocations can affect the electrical properties of semiconductors has been k n o w n for some time (16), and recent papers by Booyens, Vermaak, and Proto (17,18), and Esquivel, Sen, and Lin (19) have discussed the electrical anisotropy of a and ~ dislocations in III-V compounds as they affect carrier mobility. In the present case, an increase in electrical carrier mobility by a factor ~1.3 was demonstrated for hot implants at 150-200 keV and, earlier, an increase by a factor of ~.,2 (7) for 1 MeV implants.…”

Section: Discussionmentioning

confidence: 99%

Electron Microscope Study of Annealed SiH2 + Implanted InP

Comer

Davies

Lorenzo

1980

J. Electrochem. Soc.

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Transmission electron microscopy was used to characterize structural defects in annealed InP implanted both at room temperature and at 200~ with 1014 SiH2+/cm 2 at 150 keV. During implantation at room temperature an amorphous layer was formed to a depth of ,..1850A, whereas no such layer was formed on the specimen implanted at 200~ Upon recrystallization of the amorphous layer at 650~ or higher shear dislocations were observed as well as loop structures up to 2000A in diameter on {111} and (II0} planes within that region. Smaller, interstitial loops were present on (110} planes throughout the implanted region. The specimens implanted at 200~ did not go through a recrystallization stage. Therefore, no shear dislocations were formed in this case. However, these specimens when annealed to 650~ or higher contained loops under i00.~ in size. The structural differences observed between the room temperature and 200~ implants may account for the higher carrier mobility measured for the 200~ implant.Structural damage resulting from ion implantation in elemental semiconductors such as silicon (1-5) and the III-V semiconductors, notably GaAs (6), has been studied extensively by transmission electron microscopy. A correlation was sometimes found between the extent of damage formed and the electrical behavior of the material after postimplantation annealing to obtain maximum electrical activity.In ion implantation, damage results from displacement of atoms in the crystal lattice, causing the introduction of interstitial atoms and vacancy sites. When the specimen is annealed these defects, aggregate to form dislocation loops. At high fluences, the damage may be severe enough to form an amorphous layer near the surface of the specimen. When this occurs, the postanneal temperature must be sufficiently high to bring about epitaxial regrowth of the layer. Earlier work on Si-implanted InP in which the substrate was heated to 200~ during the implantation suggested that an amorphous layer does not form under these conditions (7). The present work shows that, for room temperature implants, not only does an amorphous layer form at the surface but, also, that following postimplantation annealing the loop structures for these implants are much larger than the defects found in the hot implants under similar annealing conditions.Whether the ion implantation method is used to form semi-insulating regions in InP or for conventional doping it is important to know the structural damage that occurs because of the effect it may have on device performance. To this end, transmission electron microscope studies were made of annealed InP implanted at room temperature and at 200~ Defects formed under various annealing conditions have been characterized and the results of electrical measurements are presented to show how they may be affected by the defects. ExperimentalThe InP used in these experiments was grown in these laboratories by the Czochralski encapsulation method and was doped with 1016 Fe/cm 3. Wafers were cut and polished to obtain specime...

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Dislocations and the piezoelectric effect in III-V crystals

Cited by 31 publications

References 14 publications

Evolution of structural and electronic properties of highly mismatched InSb films

Evolution of structural and electronic properties of highly mismatched InSb films

Piezoelectric polarization associated with dislocations in wurtzite GaN

Electron Microscope Study of Annealed SiH2 + Implanted InP

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