共查询到20条相似文献,搜索用时 0 毫秒
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J. D. Benson L. O. Bubulac P. J. Smith R. N. Jacobs J. K. Markunas M. Jaime-Vasquez L. A. Almeida A. Stoltz P. S. Wijewarnasuriya G. Brill Y. Chen J. Peterson M. Reddy M. F. Vilela S. M. Johnson D. D. Lofgreen A. Yulius G. Bostrup M. Carmody D. Lee S. Couture 《Journal of Electronic Materials》2014,43(11):3993-3998
State-of-the-art (112)B CdZnTe substrates were examined for near-surface tellurium precipitate-related defects. The Te precipitate density was observed to be fairly uniform throughout the bulk of the wafer, including the near-surface region. After a molecular beam epitaxy (MBE) preparation etch, exposed Te precipitates, small pits, and bumps on the (112)B surface of the CdZnTe wafer were observed. From near-infrared and dark field microscopy, the bumps and small pits on the CdZnTe surface are associated with strings of Te precipitates. Raised bumps are Te precipitates near the surface of the (112)B CdZnTe where the MBE preparation etch has not yet exposed the Te precipitate(s). An exposed Te precipitate sticking above the etched CdZnTe surface plane occurs when the MBE preparation etch rapidly undercuts a Te precipitate. Shallow surface pits are formed when the Te precipitate is completely undercut from the surrounding (112)B surface plane. The Te precipitate that was previously located at the center of the pit is liberated by the MBE preparation etch process. 相似文献
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M. Reddy J. M. Peterson T. Vang J. A. Franklin M. F. Vilela K. Olsson E. A. Patten W. A. Radford J. W. Bangs L. Melkonian E. P. G. Smith D. D. Lofgreen S. M. Johnson 《Journal of Electronic Materials》2011,40(8):1706-1716
This paper presents the status of HgCdTe growth on large-area Si and CdZnTe substrates at Raytheon Vision Systems (RVS). The different technological tools that were used to scale up the growth from 4 inch to 6 inch diameter on Si and from 4 cm × 4 cm to 8 cm × 8 cm on CdZnTe without sacrificing the quality of the layers are described. Extremely high compositional uniformity and low macrodefect density were achieved for single- and two-color HgCdTe layers on both Si and CdZnTe substrates. Finally, a few examples of detector and focal-plane array results are included to highlight the importance of high compositional uniformity and uniformly low macrodefect density of the epitaxial layers in obtaining high operability and low cluster outages in single- and two-color focal-plane arrays (FPAs). 相似文献
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M. Reddy J. M. Peterson S. M. Johnson T. Vang J. A. Franklin E. A. Patten W. A. Radford J. W. Bangs D. D. Lofgreen 《Journal of Electronic Materials》2009,38(8):1764-1770
This paper presents the progress in the molecular beam epitaxy (MBE) growth of HgCdTe on large-area Si and CdZnTe substrates
at Raytheon Vision Systems. We report a very high-quality HgCdTe growth, for the first time, on an 8 cm × 8 cm CdZnTe substrate.
This paper also describes the excellent HgCdTe growth repeatability on multiple 7 cm × 7 cm CdZnTe substrates. In order to
study the percentage wafer area yield and its consistency from run to run, small lots of dual-band long-wave infrared/long-wave
infrared triple-layer heterojunction (TLHJ) layers on 5 cm × 5 cm CdZnTe substrates and single-color double-layer heterojunction
(DLHJ) layers on 6-inch Si substrates were grown and tested for cutoff wavelength uniformity and micro- and macrovoid defect
density and uniformity. The results show that the entire lot of 12 DLHJ-HgCdTe layers on 6-inch Si wafers meet the testing
criterion of cutoff wavelength within the range 4.76 ± 0.1 μm at 130 K and micro- and macrovoid defect density of ≤50 cm−2 and 5 cm−2, respectively. Likewise, five out of six dual-band TLHJ-HgCdTe layers on 5 cm × 5 cm CdZnTe substrates meet the testing criterion
of cutoff wavelength within the range 6.3 ± 0.1 μm at 300 K and micro- and macrovoid defect density of ≤2000 cm−2 and 500 cm−2, respectively, on the entire wafer area. Overall we have found that scaling our HgCdTe MBE process to a 10-inch MBE system
has provided significant benefits in terms of both wafer uniformity and quality. 相似文献
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F. Erdem Arkun Dennis D. Edwall Jon Ellsworth Sheri Douglas Majid Zandian Michael Carmody 《Journal of Electronic Materials》2017,46(9):5374-5378
Recent advances in growth of Hg1?x Cd x Te films on large-area (7 cm × 7.5 cm) CdZnTe (CZT) substrates is presented. Growth of Hg1?x Cd x Te with good uniformity on large-area wafers is achieved using a Riber 412 molecular beam epitaxy (MBE) tool designed for growth of Hg1?x Cd x Te compounds. The reactor is equipped with conventional CdTe, Te, and Hg sources for achieving uniform exposure of the wafer during growth. The composition of the Hg1?x Cd x Te compound is controlled in situ by employing a closed-loop spectral ellipsometry technique to achieve a cutoff wavelength (λ co) of 14 μm at 78 K. We present data on the thickness and composition uniformity of films grown for large-format focal-plane array applications. The composition and thickness nonuniformity are determined to be <1% over the area of a 7 cm × 7.5 cm wafer. The films are further characterized by Fourier-transform infrared spectroscopy, optical microscopy, and Hall measurements. Additionally, defect maps show the spatial distribution of defects generated during the epitaxial growth of the Hg1?x Cd x Te films. Microdefect densities are in the low 103 cm?2 range, and void defects are below 500 cm?2. Dislocation densities less than 5 × 105 cm?2 are routinely achieved for Hg1?x Cd x Te films grown on CZT substrates. HgCdTe 4k × 4k focal-plane arrays with 15 μm pitch for astronomical wide-area infrared imagers have been produced using the recently developed MBE growth process at Teledyne Imaging Sensors. 相似文献
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J. D. Benson L. O. Bubulac M. Jaime-Vasquez J. M. Arias P. J. Smith R. N. Jacobs J. K. Markunas L. A. Almeida A. Stoltz P. S. Wijewarnasuriya J. Peterson M. Reddy K. Jones S. M. Johnson D. D. Lofgreen 《Journal of Electronic Materials》2017,46(9):5418-5423
The highest sensitivity, lowest dark current infrared focal plane arrays (IRFPAs) are produced using HgCdTe on CdZnTe substrates. As-received state-of-the-art CdZnTe 6 × 6 and 7 × 7.5 cm substrates were analyzed using Nomarski phase contrast microscopy, Auger electron spectroscopy, scanning electron microscopy/energy dispersive spectroscopy, and scanning profilometry. On all CdZnTe substrates tested, we observed as-received large area macro-defect contamination. Using a defect specification limit of 50 contiguous defective pixels, we identified non-compliant 1280 × 720 12-μm pitch focal plane arrays due to as-received substrate macro-defect contamination. Using the above specification, up to 20% IRFPA wafer yield loss is due to state-of-the-art as-received CdZnTe substrate macro-contamination. 相似文献
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M. Reddy W. A. Radford D. D. Lofgreen K. R. Olsson J. M. Peterson S. M. Johnson 《Journal of Electronic Materials》2014,43(8):2991-2997
HgCdTe dual-band epitaxial layers on lattice-matched CdZnTe substrates often have morphological defects. These defects, unlike normal void and microvoid defects, do not contain a polycrystalline core and, therefore, do not offer a good contrast for observation using optical and electron microscopes. This paper reports a way of identifying these defects by using a Nomarski optical microscopy image overlay on focused ion beam microscopy images for preparation of thin cross-sectional foils of these defects. Transmission electron microscopy was used to study the defect cross-sections to identify the origin and evolution of the morphological defects and their effect on the epitaxial layer. This paper reports cross-sectional analysis of four morphological defects of different shape and size. 相似文献
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主要报道了用于提高液相外延(Liquid Phase Epitaxy, LPE)长波碲镉汞薄膜质量的碲锌镉衬底筛选方法研究。通过对碲锌镉衬底的锌组分、红外透过率、沉淀/夹杂、位错密度、X射线形貌像和X射线衍射半峰宽等参数进行全面测试以及对外延后碲镉汞薄膜的X射线形貌像和X射线衍射半峰宽进行测试评估,发现目前X射线形貌像和锌组分是影响LPE长波碲镉汞薄膜用碲锌镉衬底的重要参数。结果表明,锌组分处于4.2%~4.8%之间、形貌像衍射强度高且均匀性好是长波碲镉汞薄膜外延用衬底的理想选择。 相似文献
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T. S. Lee K. K. Choi Y. T. Jeoung H. K. Kim J. M. Kim Y. H. Kim J. M. Chang W. S. Song S. U. Kim M. J. Park S. D. Lee 《Journal of Electronic Materials》1997,26(6):552-555
In this paper, we report the results of capacitance-voltage measurements conducted on several metal-insulator semiconductor (MIS) capacitors in which HgCdTe surfaces are treated with various surface etching and oxidation processes. CdZnTe passivation layers were deposited on HgCdTe surfaces by thermal evaporation after the surfaces were etched with 0.5?2.0% bromine in methanol solution, or thin oxide layers (tox ~ few ten Å) were grown on the surfaces, in order to investigate effects of the surface treatments on the electrical properties of the surfaces, as determined from capacitance-voltage (C-V) measurements at 80K and 1 MHz. A negative flat band voltage has been observed for MIS capacitors fabricated after etching of HgCdTe surfaces with bromine in methanol solutions, which is reported to make the surface Te-rich. It is inferred that residual Te on the surface is a positive charge, Te4+. C-V characteristics for MIS capacitors fabricated on oxide surfaces grown by air-exposure and electrolytic process have shown large hysteresis effects, from which it is inferred that imperfect and electrically active oxide compounds and HgTe particles near the surface become slow interface states. 相似文献
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B. Asici H. C. Eroglu Y. Ergunt A. San S. Ozer 《Journal of Electronic Materials》2018,47(10):5735-5741
High quality CdZnTe substrates with 4% ZnTe mole fraction are used for epitaxial growth of HgCdTe infrared detector layers. Molecular Beam Epitaxy (MBE) growth of HgCdTe epilayers requires high quality surface layer with sub-nanometer surface roughness values as well. We report on the development of a CdZnTe substrate surface preparation process for MBE growth of high quality HgCdTe epilayers. Surface preparation processes were performed on both commercially available CdZnTe substrates and substrates obtained from in-house grown CdZnTe boules. We developed a multi-step substrate surface processing flow to achieve sub-nanometer surface roughness, low total thickness variation (TTV), and wax or slurry residue free CdZnTe substrate surfaces. Each process step was optimized with the aim of removing the subsurface damage caused by the previous process step; so that we reduce the amount of damaged layer needed to be etched prior to epitaxy. Our developed surface preparation process can be applicable to commercially available CdZnTe substrates with high surface roughness and high TTV. This process was also optimized for as-cut CdZnTe slices. We are capable of processing typically 25 mm?×?25 mm CdZnTe substrates with achievable surface roughness values (Rrms) down to below 0.5 nm. 相似文献
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Fengfeng Sheng Jianrong Yang Shiwen Sun Changhe Zhou Huixian Yu 《Journal of Electronic Materials》2014,43(7):2702-2708
The influence of Cd-rich annealing at temperatures of 440–900 °C on the defect properties of Te-rich CdZnTe materials was studied. Cd-rich annealing at temperatures above the melting point of Te was confirmed to effectively reduce the size of Te-rich inclusions in the materials. However, dislocation multiplication occurred in the regions near Te-rich inclusions. Etch pit clusters were observed on the surfaces of annealed materials etched with Everson etchant. The etch pit clusters were much larger than the as-grown Te-rich inclusions. The dependence of the cluster size on that of the Te-rich inclusions and the annealing conditions was investigated. The density of etch pits in the normal region increased when the annealing temperature exceeded 750 °C. The mechanisms of the evolution of the Te-rich inclusions and the formation of new defects during the Cd-rich annealing are discussed. 相似文献
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文章报道了采用液相外延方法,在碲锌镉衬底上进行碲锌镉薄膜缓冲层生长的情况,并且采用X光双晶衍射仪、X光形貌仪、红外傅里叶光谱仪、二次离子质谱仪等手段对碲锌镉薄膜进行了表征,碲锌镉薄膜具有较好地组分及均匀性,晶体结构质量也较好。采用碲锌镉缓冲结构生长了碲镉汞液相外延片,其碲锌镉与碲镉汞薄膜界面附近的杂质得到了有效的控制。 相似文献
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J.D. Benson L.A. Almeida M.W. Carmody D.D. Edwall J.K. Markunas R.N. Jacobs M. Martinka U. Lee 《Journal of Electronic Materials》2007,36(8):949-957
The as-grown molecular beam epitaxy (MBE) (211)B HgCdTe surface has variable surface topography, which is primarily dependent on substrate temperature and substrate/epilayer mismatch. Nano-ripple formation and cross-hatch patterning are the predominant structural features observed. Nano-ripples preferentially form parallel to the \( [\bar {1}11] \) and are from 0 Å to 100 Å in height with a wavelength between 0.1 μm and 0.8 μm. Cross-hatch patterns result from slip dislocations in the three {111} planes intersecting the (211) growth surface. The cross-hatch step height is 4 ± 1 Å (limited data set). This indicates that only a bi-layer slip (Hg/Cd + Te) in the {111} slip plane occurs. For the deposition of MBE (211)B HgCdTe/CdTe/Si, the reorientation of multiple nano-ripples coalesced into “packets” forms cross-hatch patterns. The as-grown MBE (211)B CdTe/Si surface is highly variable but displays nano-ripples and no cross-hatch pattern. Three types of defects were observed by atomic force microscopy (AFM): needle, void/hillock, and voids. 相似文献