Jim Bangs - Academia.edu (original) (raw)

Papers by Jim Bangs

SEG Technical Program Expanded Abstracts 1992, 1992

Reverse Vertical Seismic Profiling VSP and interwell seismic experiments were conducted at the We... more Reverse Vertical Seismic Profiling VSP and interwell seismic experiments were conducted at the Western Kentucky Petroleum Buckhorn test site near Quincy, Illinois. The RVSP data were acquired using a 3-component pneumatic probe and the interwell seismic data were acquired using a 24-element hydrophone array. The experiments were conducted to analyze high resolution seismic waveforms and to perform travel time velocity inversion for mapping the Silurian Kankakee formation which is the more prolific oil producer in the Mt. Sterling area. Reverse VSP and interwell seismic measurements together with log data have yielded information on the anisotropic characteristic of the shale formation and in the compressional wave velocity distribution of the limestone formation. These results inferred that reverse VSP (using several 3-component detectors in shallow boreholes) and interwell seismic measurements integrated with log data and seismic modeling can delineate the hydrocarbon reservoir and geological structures at the Buckhorn test site.

The Journal of Pediatrics, 1962

Journal of Biological Chemistry, 2013

Background: Nucleotide sugar transporters (NSTs) provide availability of nucleotide sugars for gl... more Background: Nucleotide sugar transporters (NSTs) provide availability of nucleotide sugars for glycosylation in the lumen of the Golgi apparatus. Results: The substrate specificities of four Trypanosoma brucei NSTs were characterized, and inhibition of TbNST4 resulted in glycosylation defects. Conclusion: TbNST4 plays an essential role in biosynthesis of glycoproteins in T. brucei. Significance: To understand the roles of TbNST(s) in the growth and pathogenesis of T. brucei.

Applied Biochemistry and Biotechnology, 2007

*Author to whom all correspondence and reprint requests should be addressed. Current address: De... more *Author to whom all correspondence and reprint requests should be addressed. Current address: Department of Medical Research and Technology, University of Maryland School of Medicine, 100 Penn Street, Baltimore, MD 21201, E-mail: CLouime@ som.umaryland.edu

Quantum Sensing and Nanophotonic Devices III, 2006

Raytheon Vision Systems (RVS) is developing two-color and large format single color FPAs fabricat... more Raytheon Vision Systems (RVS) is developing two-color and large format single color FPAs fabricated from molecular beam epitaxy (MBE) grown HgCdTe triple layer heterojunction (TLHJ) wafers on CdZnTe substrates and double layer heterojunction (DLHJ) wafers on Si substrates, respectively. MBE material growth development has resulted in scaling TLHJ growth on CdZnTe substrates from 10cm 2 to 50cm 2 , long-wavelength infrared (LWIR) DLHJ growth on 4-inch Si substrates and the first demonstration of mid-wavelength infrared (MWIR) DLHJ growth on 6-inch Si substrates with low defect density (<1000cm-2) and excellent uniformity (composition<0.1%, cutoff wavelength ∆center-edge<0.1µm). Advanced FPA fabrication techniques such as inductively coupled plasma (ICP) etching are being used to achieve high aspect ratio mesa delineation of individual detector elements with benefits to detector performance. Recent two-color detectors with MWIR and LWIR cutoff wavelengths of 5.5µm and 10.5µm, respectively, exhibit significant improvement in 78K LW performance with >70% quantum efficiency, diffusion limited reverse bias dark currents below 300pA and RA products (zero field-of-view, +150mV bias) in excess of 1×10 3 Ωcm 2. Two-color 20µm unit-cell 1280×720 MWIR/LWIR FPAs with pixel response operability approaching 99% have been produced and high quality simultaneous imaging of the spectral bands has been achieved by mating the FPA to a readout integrated circuit (ROIC) with Time Division Multiplexed Integration (TDMI). Large format mega pixel 20µm unit-cell 2048×2048 and 25µm unit-cell 2560×512 FPAs have been demonstrated using DLHJ HgCdTe growth on Si substrates in the short wavelength infrared (SWIR) and MWIR spectral range. Recent imaging of 30µm unit-cell 256×256 LWIR FPAs with 10.0-10.7µm 78K cutoff wavelength and pixel response operability as high as 99.7% show the potential for extending HgCdTe/Si technology to LWIR wavelengths.

Polarization: Measurement, Analysis, and Remote Sensing VIII, 2008

Infrared Technology and Applications XXXII, 2006

Infrared Systems and Photoelectronic Technology, 2004

Materials for Infrared Detectors, 2001

Journal of Electronic Materials, 2006

This article details current-voltage characteristics for a very long wavelength infrared (VLWIR) ... more This article details current-voltage characteristics for a very long wavelength infrared (VLWIR) Hg 1ÿ x Cd x Te detector from Raytheon Vision Systems with a cutoff wavelength of 20.0 mm at 28 K. In this article, the VLWIR detector diode currents are modeled as a function of bias and temperature. This in-depth current model includes diffusion, band-to-band tunneling, trap-assisted tunneling (TAT), and shunt currents. The trap density has been extracted from the modeled TAT component of the current and was revealed to be relatively temperature-independent. An attempted incorporation of VLWIR detector susceptibility to stress has also been included through variation of the model parameter associated with the p-n junction electric field strength. This field variation accounts for stress induced piezoelectric fields. The current in this VLWIR detector was found to be diffusion-limited under much of the temperature and bias ranges analyzed. This modeling allows the scrutiny of both the dominant current-limiting mechanism and the magnitudes of the various current components as a function of both bias and temperature, allowing the straightforward determination of the ideal operating conditions for a given detector.

Journal of Electronic Materials, 2005

An automated iterative nonlinear fitting program has been developed to model current-voltage (I-V... more An automated iterative nonlinear fitting program has been developed to model current-voltage (I-V) data measured on HgCdTe infrared (IR) detector diodes. This model includes the ideal diode diffusion, generation-recombination, bandto-band tunneling, trap-assisted tunneling (TAT), and avalanche breakdown as potential current limiting mechanisms in an IR detector diode. The modeling presented herein allows one to easily distinguish, and more importantly to quantitatively compare, the amount of influence each current limiting mechanism has on various detectors' I-V characteristics. Longer cutoff wavelength detectors often exhibit significant current limitations due to tunneling processes. The temperature dependence of these tunneling characteristics is thoroughly investigated for two diodes.

Proceedings of SPIE, 2011

High-performance large-format detector arrays responsive to the 1-5mum wavelength range of the in... more High-performance large-format detector arrays responsive to the 1-5mum wavelength range of the infrared spectrum fabricated using large area HgCdTe layers grown on 6-inch diameter (211) silicon substrates are available for advanced imaging applications. This paper reviews performance and capabilities of Raytheon Vision Systems (RVS) HgCdTe/Si Focal Plane Arrays (FPA) and shows 2k x 2k format MWIR HgCdTe/Si FPA performance with

SPIE Optical Engineering + Applications, 2011

Large format detector arrays are responsive uniformly over spectral 1-5µm wavelength range and ar... more Large format detector arrays are responsive uniformly over spectral 1-5µm wavelength range and are available with RVS' high quality HgCdTe detector epitaxial layers on large area 15 cm diameter wafers. Large wafers enable both low cost High Definition (HD) staring FPAs, as well as the ability to approach giga-pixel format detector arrays with a seamless 10cm ×10cm continuous image plane size possible. With a 15 cm diameter detector substrate it is a straightforward growth path to a 5k×5k µm pitch 25 Mega-pixel infrared focal plane array (FPA) with smaller pitches allowing even greater format along the 10cm die length. This paper describes arrays 1.5 to 4 Mega-pixel infrared HgCdTe developed by RVS for demanding higher performance applications. Performance data for both the detector and ROIC for typical SWIR and MWIR FPAs operating at 85K will be presented. This paper will provide FPA performance capability for small pitch large format HgCdTe/Si detector arrays fabricated at RVS and manufacturing readiness low cost Mega-pixel infrared FPAs for current and future wide FOV high-resolution systems.

SPIE International Symposium on Optical Science and Technology, 2001

Since its initial synthesis and investigation more than 40 years ago, the HgCdTe alloy semiconduc... more Since its initial synthesis and investigation more than 40 years ago, the HgCdTe alloy semiconductor system has evolved into one of the primary infrared detector materials for high-performance infrared focal-plane arrays (FPA) designed to operate in the 3-5 µm and 8-12 µm spectral ranges of importance for thermal imaging systems. Over the course of the past decade, significant advances have been made in the development of thin-film epitaxial growth techniques, such as molecular-beam epitaxy (MBE), which have enabled the synthesis of IR detector device structures with complex doping and composition profiles. The central role played by in situ sensors for monitoring and control of the MBE growth process are reviewed. The development of MBE HgCdTe growth technology is discussed in three particular device applications: avalanche photodiodes for 1.55 µm photodetection, megapixel FPAs on Si substrates, and multispectral IR detectors.

SPIE Defense and Security Symposium, 2010

Raytheon Vision Systems (RVS) is producing large format, high definition HgCdTe-based MWIR and SW... more Raytheon Vision Systems (RVS) is producing large format, high definition HgCdTe-based MWIR and SWIR focal plane arrays (FPAs) with pitches of 15 µm and smaller for various applications. Infrared sensors fabricated from HgCdTe have several advantages when compared to those fabricated from other materials-such as a highly tunable bandgap, high quantum efficiencies, and R 0 A approaching theoretical limits. It is desirable to operate infrared sensors at elevated operating temperatures in order to increase the cooler life and reduce the required system power. However, the sensitivity of many infrared sensors, including those made from HgCdTe, declines significantly above a certain temperature due to the noise resulting from increasing detector dark current. In this paper we provide performance data on a MWIR and a SWIR focal plane array operating at temperatures up to 160K and 170K, respectively. The FPAs used in the study were grown by molecular beam epitaxy (MBE) on silicon substrates, processed into a 1536x1024 format with a 15 µm pixel pitch, and hybridized to a silicon readout integrated circuit (ROIC) via indium bumps to form a sensor chip assembly (SCA). This data shows that the noise equivalent delta temperature (NEDT) is background limited at f/3.4 in the SWIR SCA (cutoff wavelength of 3.7 µm at 130K) up to 140K and in the MWIR SCA (cutoff wavelength of 4.8 µm at 115K) up to 115K.

SPIE Defense and Security Symposium,, 2006

This paper presents the infrared detector performance improvement accomplishments by Raytheon Vis... more This paper presents the infrared detector performance improvement accomplishments by Raytheon Vision Systems (RVS) and by AVYD Devices Inc (AVYD). The RVS-AVYD collaboration has resulted in the demonstration of very large imaging focal plane arrays with respectable operability and performance which could potentially be useful in a variety of promising new applications to advance performance capability for future near and short wave infrared imaging missions. This detector design concept potentially permits ultra-small pixel large format imaging capabilities for diffraction limited resolution down to 5µm pitch focal planes. In this paper, we report on the work performed at the RVS's advanced prototype engineering facility, to fabricate planar detector array wafers with a combination of RVS's Hg 1-x Cd x Te production material growth and detector fabrication processes and AVYD's p-type ion-implantation process. This paper will review the performance of a 20µm pitch 1,024 X 1,024 format SWIR focal plane array. The detector array was fabricated in Hg 1-x Cd x Te material responsive from near-infrared to 2.5µm cutoff wavelength. Imaging capability was achieved via interconnect bump bond connection of this detector array to an RVS astronomy grade readout chip. These focal plane arrays have exhibited outstanding quantum efficiency uniformity and magnitude over the entire spectral range and in addition, have also exhibited very low leakage current with median values of 0.25 electrons per second. Detector arrays were processed in engineering grade Hg 1-x Cd x Te epitaxial layers grown with a modified liquid phase epitaxy process on CdZnTe substrates followed by a combination of passivation/ion implantation/passivation steps. This paper will review the detector performance data in detail including the test structure current-voltage plots, spectral cutoff curves, FPA quantum efficiency, and leakage current.

Journal of Electronic Materials, 2015

Dark current density data recorded over the past 14 years at Raytheon Vision Systems on short-wav... more Dark current density data recorded over the past 14 years at Raytheon Vision Systems on short-wavelength infrared (SWIR) and medium-wavelength infrared (MWIR) devices were examined. This included HgCdTe detector arrays grown by liquid-phase epitaxy on CdZnTe and molecular beam epitaxy on both silicon and CdZnTe substrates. This study analyzed zero-bias resistance-area product and current-voltage measurements from test structure assemblies included on every detector wafer. The data span cutoff wavelengths from 1.7 lm to 7.5 lm and operating temperatures from 40 K to 300 K. A basis is derived for a simple manufacturing trend model for a wide range of cutoffs and temperatures. This model uses a function similar to Tennant's Rule'07 but includes a generation-recombination (GR) term. Dark current densities below the test set limit are extrapolated assuming GR-limited performance. Model assumptions are tested using sensor chip assembly (SCA) median dark current density values at the same inverse cutoff-temperature products. This model allows probabilistic determination of array manufacturability and prediction of yield, and provides a statistical basis for Raytheon's state-of-the-art performance.

Proceeding of SPIE 8012, Infrared Technology and Applications XXXVII, 2011

High-performance large-format detector arrays responsive to the 1-5µm wavelength range of the inf... more High-performance large-format detector arrays responsive to the 1-5µm wavelength range of the infrared spectrum fabricated using large area HgCdTe layers grown on 6-inch diameter (211) silicon substrates are available for advanced imaging applications. This paper reviews performance and capabilities of Raytheon Vision Systems (RVS) HgCdTe/Si Focal Plane Arrays (FPA) and shows 2k x 2k format MWIR HgCdTe/Si FPA performance with NEdT operabilities better than 99.9%. SWIR and MWIR detector performance for HgCdTe/Si is comparable to established performance of HgCdTe/CdZnTe wafers. HgCdTe devices fabricated on both types of substrates have demonstrated very low dark current, high quantum efficiency and full spectral band fill factor characteristic of HgCdTe. HgCdTe has the advantage of being able to precisely tune the detector cutoff via adjustment of the Cd composition in the MBE growth. The HgCdTe/Si detectors described in this paper are p-on-n mesa delineated architecture and fabricated using the same mature etch, passivation, and metallization processes as our HgCdTe/CdZnTe line. Uniform device quality HgCdTe epitaxial layers and application of detector fabrication processes across the full area of 6-inch wafers routinely produces high performing detector pixels from edge to edge of the photolithographic limits across the wafer, offering 5 times the printable area as costly 6×6cm CdZnTe substrates. This 6-inch HgCdTe detector wafer technology can provide applications demanding very wide FOV high resolution coverage the capability to produce a very large single piece infrared detector array, up to a continuous image plane 10×10 cm in size. Alternatively, significant detector cost reduction through allowing more die of a given size to be printed on each wafer is possible, with further cost reduction achieved through transition towards automated detector fabrication and photolithographic processes for both increased yields and reduced touch labor costs. RVS continues to improve its FPA manufacturing line towards achieving low cost infrared FPAs with the format, size, affordability, and performance required for current and future infrared applications.

Journal of Elec Material, 2011

This paper presents the status of HgCdTe growth on large-area Si and CdZnTe substrates at Raytheo... more 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 9 4 cm to 8 cm 9 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).