Imaging photovoltaic infrared CdHgTe detectors

Haakenaasen, R.; Steen, H.; Selvig, E.; Lorentzen, T.; Rheenen, Arthur D. van; Trosdahl-Iversen, L.; Hall, D.; Gordon, Neil T.; Skauli, T.; Vaskinn, Asle Heide

doi:10.1088/0031-8949/2006/t126/007

Cited by 12 publications

(10 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…defects 51-53 or, specifically, high-temperature voids. 54,55 These defects can nucleate at any depth, and occur with different sizes. A summary of an associated nanospectroscopy study was given by Aoki et al 22 Other kinds of voids are caused by dust particles left on the surface by, or in spite of, the substrate cleaning process, such as contaminated deionized water.…”

Section: Resultsmentioning

confidence: 99%

Surface Morphology and Defect Formation Mechanisms for HgCdTe (211)B Grown by Molecular Beam Epitaxy

Chang

Becker

Grein

et al. 2008

Journal of Elec Materi

View full text Add to dashboard Cite

The surface morphology and crystallinity of HgCdTe films grown by molecular beam epitaxy (MBE) on both CdZnTe and CdTe/Si (211)B substrates were characterized using atomic force microscopy (AFM), as well as scanning (SEM) and transmission (TEM) electron microscopy. Crosshatch patterns and sandybeach-like morphologies were commonly found on MBE (211) HgCdTe epilayers grown on both CdZnTe and CdTe/Si substrates. The patterns were oriented along the 213 Â Ã , 231 Â Ã , and 011 Â Ã directions, which were associated with the intersection between the (211) growth plane and each of the eight equivalent HgCdTe slip planes. This was caused by strain-driven operation of slip in these systems with relative large Schmid factor, and was accompanied by dislocation formation as well as surface strain relief. Surface crater defects were associated with relatively high growth temperature and/or low Hg flux, whereas microtwins were associated with relatively low growth temperature and/or high Hg flux. AFM and electron microscopy were used to reveal the formation mechanisms of these defects. HgCdTe/HgCdTe superlattices with layer composition differences of less than 2% were grown by MBE on CdZnTe substrates in order to clarify the formation mechanisms of void defects. The micrographs directly revealed the spiral nature of growth, hence demonstrating that the formation of void defects could be associated with the Burton, Cabrera, and Frank (BCF) growth mode. Void defects, including microvoids and craters, were caused by screw defect clusters, which could be triggered by Te precipitates, impurities, dust, other contamination or flakes. Needle defects originated from screw defect clusters linearly aligned along the 011 Â Ã directions with opposite Burgers vector directions. They were visible in HgCdTe epilayers grown on interfacial superlattices. Hillocks were generated owing to twin growth of void or needle defects on (111) planes due to low growth temperature and the corresponding insufficient Hg movement on the growth surface. Therefore, in addition to nucleation and growth of HgCdTe in the normal two-dimensional layer growth mode, the BCF growth mode played an important role and should be taken into account during investigation of HgCdTe MBE growth mechanisms.

show abstract

Section: Resultsmentioning

confidence: 99%

Surface Morphology and Defect Formation Mechanisms for HgCdTe (211)B Grown by Molecular Beam Epitaxy

Chang

Becker

Grein

et al. 2008

Journal of Elec Materi

View full text Add to dashboard Cite

show abstract

“…MCT structures grown by molecular beam epitaxy (MBE) have become a basic material for developing infrared focal plane arrays, including those for third--generation infrared detectors [7][8][9]. Though MBE MCT technology is now quite mature, it still faces a number of challenges related to the presence of a considerable number of structural and point defects in the films grown on foreign (GaAs or Si) substrates.…”

Section: Introductionmentioning

confidence: 99%

Study of the Defect Structure of Hg_1-xCd_xTe Films by Ion Milling

Pociask

Іжнін²,

Ilyina³

et al. 2008

Acta Phys. Pol. A

View full text Add to dashboard Cite

A study of the defect structure of heteroepitaxially grown Hg1−xCdxTe (MCT) films was performed with the use of ion milling. Undoped and in situ As-(acceptor) or In-(donor) doped films with x = 0.22, grown by molecular beam epitaxy on GaAs substrates, as-grown and annealed, were subjected to ion milling with subsequent electrical characterization. The results obtained on the MBE films were compared to those acquired on wafers cut from bulk crystals, and on epitaxial films grown by liquid and vapor phase epitaxy. In all the MBE films ion milling revealed a presence of a neutral defect with concentration ≈ 10 17 cm −3 , formed at the stage of the growth. Residual donor concentration in the films was found to be of the order of 10 15 cm −3 , which is typical of high-quality MCT.

show abstract

“…We have not been able to associate needles with dislocations (through Hä hnert and Schenk dislocation etch and XRD full width half maximum measurements, FWHM) or twinning around the [111] axis (through reflection high-energy electron diffraction (RHEED) observations, XRD twin reflection measurements, and etch pit studies). 18 Needle lengths were unaffected by defect etching. AFM volume calculations indicate that all the missing material in the depression is found in the ridge.…”

Section: (211)b Cdhgte Surface Morphologymentioning

confidence: 98%

“…22 We believe the needles have been formed by preferential Te surface diffusion during growth, as explained in the next section. 18 Defect densities are plotted versus temperature in Fig. 7.…”

Section: (211)b Cdhgte Surface Morphologymentioning

confidence: 99%

“…8). [18][19][20][21] The needles consist of a trench and a material build-up on one side of the trench. We have found that the density of needles is reduced after a bake-out of the growth chamber, but also that the density of needles are reduced if a few thin alternating layers of CdTe and CdHgTe are grown between the substrate and the thick CdHgTe layer.…”

Section: Formation Of Microvoids and Needles In (211)b-oriented Layersmentioning

confidence: 99%

See 1 more Smart Citation

Defects in HgTe and CdHgTe Grown by Molecular Beam Epitaxy

Selvig

Tonheim

Lorentzen

et al. 2008

Journal of Elec Materi

View full text Add to dashboard Cite

The defect morphology in HgTe and CdHgTe was studied in (211)B-oriented layers grown in a 20°C temperature range around the optimal growth temperature. The density of defects varies strongly with the growth temperature. In HgTe, the shape of the microvoid defects is very sensitive to the growth temperature and can be used to determine the deviation from the optimal growth temperature. Using thermodynamical modeling, the optimal growth temperature for CdHgTe can then be calculated. We describe a mechanism for the formation of microvoids and needles which involves preferential surface diffusion of Te combined with an impurity or defect on the substrate. Microvoids on (111)B-oriented partially twinned HgTe layers were also studied. The microvoids in the twinned parts of the layer were found to be rotated 180 deg relative to the untwinned parts of the layer.

show abstract

Imaging photovoltaic infrared CdHgTe detectors

Cited by 12 publications

References 17 publications

Surface Morphology and Defect Formation Mechanisms for HgCdTe (211)B Grown by Molecular Beam Epitaxy

Surface Morphology and Defect Formation Mechanisms for HgCdTe (211)B Grown by Molecular Beam Epitaxy

Study of the Defect Structure of Hg_1-xCd_xTe Films by Ion Milling

Defects in HgTe and CdHgTe Grown by Molecular Beam Epitaxy

Contact Info

Product

Resources

About

Imaging photovoltaic infrared CdHgTe detectors

Cited by 12 publications

References 17 publications

Surface Morphology and Defect Formation Mechanisms for HgCdTe (211)B Grown by Molecular Beam Epitaxy

Surface Morphology and Defect Formation Mechanisms for HgCdTe (211)B Grown by Molecular Beam Epitaxy

Study of the Defect Structure of Hg1-xCdxTe Films by Ion Milling

Defects in HgTe and CdHgTe Grown by Molecular Beam Epitaxy

Contact Info

Product

Resources

About

Study of the Defect Structure of Hg_1-xCd_xTe Films by Ion Milling