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Article
In Situ Band-Edge Monitoring of Cd1−yZnyTe Substrates for Molecular Beam Epitaxy of HgCdTe
We demonstrate the benefits of in situ band-edge monitoring of CdZnTe substrates for molecular beam epitaxy (MBE). The production of large-area Cd1−yZnyTe(211)B substrates up to and exceeding 8 × 8 cm2 brings new...
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Article
Defects and the Formation of Impurity ‘Hot Spots’ in HgCdTe/CdZnTe
The formation of impurity ‘hot spot’ macro-defects—localized high impurity level contaminates—is examined. The evolution of macro-defects through their critical stages: as-received CdZnTe substrate, molecular ...
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Article
Impurity ‘Hot Spots’ in MBE HgCdTe/CdZnTe
In this work, impurity ‘hot spot’ macro-defects—high impurity level macro-defect contaminates were examined. ‘Hot spots’ have very high localized concentrations of: K, Mg, Ni, Cr, Mn, Ca, Al, Na, Fe, and Cu. F...
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Article
Impact of CdZnTe Substrates on MBE HgCdTe Deposition
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 analyz...
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Article
Correlation of Etch Pits and Dislocations in As-grown and Thermal Cycle-Annealed HgCdTe(211) Films
This paper reports observations of the different types of etch pits and dislocations present in thick HgCdTe (211) layers grown by molecular beam epitaxy on CdTe/Si (211) composite substrates. Dislocation anal...
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Article
Analysis of Etched CdZnTe Substrates
State-of-the-art as-received (112)B CdZnTe substrates have been examined for surface impurity contamination and polishing residue. Two 4 cm × 4 cm and one 6 cm × 6 cm (112)B state-of-the-art as-received CdZnTe...
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Article
As-Received CdZnTe Substrate Contamination
State-of-the-art as-received (112)B CdZnTe substrates were examined for surface impurity contamination, polishing damage, and tellurium precipitates/inclusions. A maximum surface impurity concentration of Al =...
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Article
Dynamic Curvature and Stress Studies for MBE CdTe on Si and GaAs Substrates
Infrared focal plane arrays (IRFPA) based on HgCdTe semiconductor alloys have been shown to be ideal for tactical and strategic applications. High density (>1 M pixel), high operability HgCdTe detectors on lar...
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Article
Impact of Tellurium Precipitates in CdZnTe Substrates on MBE HgCdTe Deposition
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, in...
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Article
Analysis of Mesa Dislocation Gettering in HgCdTe/CdTe/Si(211) by Scanning Transmission Electron Microscopy
Due to its strong infrared absorption and variable band-gap, HgCdTe is the ideal detector material for high-performance infrared focal-plane arrays (IRFPAs). Next-generation IRFPAs will utilize dual-color high...
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Article
TEM Characterization of HgCdTe/CdTe Grown on GaAs(211)B Substrates
A microstructural study of HgCdTe/CdTe/GaAs(211)B and CdTe/GaAs(211)B heterostructures grown using molecular beam epitaxy (MBE) was carried out using transmission electron microscopy and small-probe microanaly...
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Article
Variable-Field Hall Measurement and Transport in LW Single-Layer n-Type MBE Hg1−x Cd x Te
Molecular beam epitaxy n-type long-wavelength infrared (LWIR) Hg1−x Cd x Te (MCT) has been investigated using variable-field Hall measurement in the temperature r...
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Article
The Surface Kinetics of MBE-Grown CdTe (211)B During In Situ Cyclic Annealing
The surface kinetics of CdTe (211)B grown by molecular beam epitaxy (MBE) is investigated using spectroscopic ellipsometry (SE) during in situ cyclic annealing. A method of measuring sublimation rates from high-i...
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Article
Impurity Gettering in (112)B HgCdTe/CdTe/Alternate Substrates
The crystalline structure and impurity profiles of HgCdTe/CdTe/alternate substrate (AS; Si and GaAs are possibilities) and CdTe/AS were analyzed by secondary-ion mass spectrometry, atomic force microscopy, etc...
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Article
Development of MBE II–VI Epilayers on GaAs(211)B
Large-area, low-cost substrates are envisioned for next-generation HgCdTe infrared focal-plane arrays (IRFPA). Si, GaAs, Ge, and InSb have been previously examined as potential candidates. Fabrication of IRFPA...
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Article
Real-Time In Situ Monitoring of GaAs (211) Oxide Desorption and CdTe Growth by Spectroscopic Ellipsometry
We describe the growth of CdTe (211)B by molecular beam epitaxy on large-area epiready GaAs (211)B substrates. Prior to CdTe growth, GaAs substrates were thermally cleaned under an As4 flux. Oxide desorption was ...
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Article
Understanding the Evolution of CdTe Buffer Layer Surfaces on ZnTe/Si(211) and GaAs(211)B During Cyclic Annealing
We present the results of a detailed study of the changes that occur on CdTe buffer layer surfaces grown on ZnTe/Si(211) and GaAs(211)B during the routine thermal cyclic annealing (TCA) process. Observations i...
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Article
Growth and Analysis of HgCdTe on Alternate Substrates
Dislocations generated at the HgCdTe/CdTe(buffer layer) interface are demonstrated to play a significant role in influencing the crystalline characteristics of HgCdTe epilayers on alternate substrates (AS). A ...
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Article
Microstructural Characterization of CdTe(211)B/ZnTe/Si(211) Heterostructures Grown by Molecular Beam Epitaxy
Transmission electron microscopy and small-probe microanalysis have been used to investigate the microstructure and compositional profiles of CdTe(211)B/ZnTe/Si(211) heterostructures. Thin ZnTe buffer layers a...
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Article
Si Wafer Thinning Techniques Compatible With Epitaxy of CdTe Buffer Layers
Reduction of threading dislocation density is critical for improving the performance of HgCdTe detectors on lattice-mismatched alternative substrates such as Si. CdTe buffer layers grown by molecular beam epit...
