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MBE back-illuminated silicon Geiger-mode avalanche photodiodes for enhanced ultraviolet response

April 25, 2011
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Conference Paper
Author:
Daniel R. Schuette
…
Published in:
SPIE Vol. 8033, Advanced Photon Counting Techniques V, 25 April 2011, 80330D.
Topic:
sensors
R&D area:
R&D group:

Summary

We have demonstrated a wafer-scale back-illumination process for silicon Geiger-mode avalanche photodiode arrays using Molecular Beam Epitaxy (MBE) for backside passivation. Critical to this fabrication process is support of the thin (< 10 um) detector during the MBE growth by oxide-bonding to a full-thickness silicon wafer. This back-illumination process makes it possible to build low-dark-count-rate single-photon detectors with high quantum efficiency extending to deep ultraviolet wavelengths. This paper reviews our process for fabricating MBE back-illuminated silicon Geigermode avalanche photodiode arrays and presents characterization of initial test devices.
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Summary

We have demonstrated a wafer-scale back-illumination process for silicon Geiger-mode avalanche photodiode arrays using Molecular Beam Epitaxy (MBE) for backside passivation. Critical to this fabrication process is support of the thin ( 10 um) detector during the MBE growth by oxide-bonding to a full-thickness silicon wafer. This back-illumination process makes...

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MBE back-illuminated silicon Geiger-mode avalanche photodiodes for enhanced ultraviolet response

Overlapped digital subarray architecture for multiple beam phased array radar

April 11, 2011
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Conference Paper
Author:
Jeffrey S. Herd
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Published in:
EuCAP 2011, 5th European Conf. on Antrennas and Propagation, 11-15 April 2011, pp. 3027-3030.
Topic:
radar
R&D area:
R&D group:

Summary

MIT Lincoln Laboratory is conducting a technology demonstration of affordable Multifunction Phased Array Radar (MPAR) technology for Next Generation air traffic control and national weather surveillance services. Aggressive cost and performance goals have been established for the system. The array architecture and its realization using custom Transmit and Receive Integrated Circuits and panel-based Line Replaceable Unit (LRU) will be presented. A program plan for risk reduction and system demonstration will be outlined.
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Summary

MIT Lincoln Laboratory is conducting a technology demonstration of affordable Multifunction Phased Array Radar (MPAR) technology for Next Generation air traffic control and national weather surveillance services. Aggressive cost and performance goals have been established for the system. The array architecture and its realization using custom Transmit and Receive Integrated...

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Overlapped digital subarray architecture for multiple beam phased array radar

Uniformity study of wafer-scale InP-to-silicon hybrid integration

April 1, 2011
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Journal Article
Author:
Di Liang
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Published in:
Appl. Phys. A, Mat. Sci. & Process., Vol. 103, No. 1, April 2011, pp. 213-218.
Topic:
microelectronics
R&D area:
R&D group:

Summary

In this paper we study the uniformity of up to 150 mm in diameter wafer-scale III-V epitaxial transfer to the Si-on-insulator substrate through the O2 plasma-enhanced low-temperature (300°C) direct wafer bonding. Void-free bonding is demonstrated by the scanning acoustic microscopy with sub-um resolution. The photoluminescence (PL) map shows less than 1 nm change in average peak wavelength, and even improved peak intensity (4% better) and full width at half maximum (41% better) after 150 mm in diameter epitaxial transfer. Small and uniformly distributed residual strain in all sizes of bonding, which is measured by high-resolution X-ray diffraction Omega- 2Theta mapping, and employment of a two-period InP-InGaAsP superlattice at the bonding interface contributes to the improvement of PL response. Preservation of multiple quantum-well integrity is also verified by high-resolution transmission electron microscopy.
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Summary

In this paper we study the uniformity of up to 150 mm in diameter wafer-scale III-V epitaxial transfer to the Si-on-insulator substrate through the O2 plasma-enhanced low-temperature (300°C) direct wafer bonding. Void-free bonding is demonstrated by the scanning acoustic microscopy with sub-um resolution. The photoluminescence (PL) map shows less than...

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Uniformity study of wafer-scale InP-to-silicon hybrid integration

A space-time multiscale analysis system: a sequential variational analysis approach

April 1, 2011
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Journal Article
Author:
Y. Xie
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Published in:
Monthly Weather Rev., Vol. 139, No. 4, April 2011, pp. 1224-1240.
Topic:
aviation weather
R&D area:
R&D group:

Summary

As new observation systems are developed and deployed, new and presumably more precise information is becoming available for weather forecasting and climate monitoring. To take advantage of these new observations, it is desirable to have schemes to accurately retrieve the information before statistical analyses are performed so that statistical computation can be more effectively used where it is needed most. The authors propose a sequential variational approach that possesses advantages of both a standard statistical analysis [such as with a three-dimensional variational data assimilation (3DVAR) or Kalman filter] and a traditional objective analysis (such as the Barnes analysis). The sequential variational analysis is multiscale, inhomogeneous, anisotropic, and temporally consistent, as shown by an idealized test case and observational datasets in this study. The real data cases include applications in two-dimensional and three-dimensional space and time for storm outflow boundary detection (surface application) and hurricane data assimilation (three-dimensional space application). Implemented using a multigrid technique, this sequential variational approach is a very efficient data assimilation method.
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Summary

As new observation systems are developed and deployed, new and presumably more precise information is becoming available for weather forecasting and climate monitoring. To take advantage of these new observations, it is desirable to have schemes to accurately retrieve the information before statistical analyses are performed so that statistical computation...

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A space-time multiscale analysis system: a sequential variational analysis approach

Triangle TCAS antenna

March 31, 2011
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Project Report
Author:
William H. Harman III
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Published in:
MIT Lincoln Laboratory Report ATC-380
Topic:
surveillance
R&D area:
R&D group:

Summary

The Traffic Alert and Collision Avoidance (TCAS) provides a pilot display showing the range and bearing of nearby aircraft. TCAS obtains the bearing information by using an angle-of-arrival antenna. In the development of TCAS at Lincoln Laboratory, the first airborne tests were conducted using an Adcock antenna, which is a small square array of four monopole elements. This report describes an alternative antenna for TCAS, using three elements in the shape of a triangle. It is shown that the triangle antenna is less sensitive to receiver noise, and that improvement factor is about 10 dB.
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Summary

The Traffic Alert and Collision Avoidance (TCAS) provides a pilot display showing the range and bearing of nearby aircraft. TCAS obtains the bearing information by using an angle-of-arrival antenna. In the development of TCAS at Lincoln Laboratory, the first airborne tests were conducted using an Adcock antenna, which is a...

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Triangle TCAS antenna

Route availability planning tool evaluation vizualizations for the New York and Chigaco departure flows

March 29, 2011
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Conference Paper
Author:
Ngaire K. Underhill
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Published in:
AIAA Infotech at Aerospace Conf. and Exhibit, 29-31 March 2011.
Topic:
air traffic management
R&D area:
R&D group:

Summary

When operationally significant weather affects a region of the National Airspace System (NAS) a Severe Weather Avoidance Program (SWAP) is initiated for that region. Each SWAP event is a unique mix of demand, weather conditions, traffic flow management (TFM) initiatives and traffic movement. On the day following a SWAP, the SWAP events are reviewed by FAA and airline representatives as part of the daily planning teleconference, and the TFM initiatives used are evaluated to understand their impact on the traffic flows, benefits, and disadvantages. Due to the complexity of the situation various exploratory visualizations were designed in order to evaluate aspects of the aviation environment and the responsive actions of the NAS during outbreaks of convective weather as well as to gain insights on the interaction of weather and traffic operations. From these visualizations, analyses and metrics were developed that could be used to objectively evaluate the effectiveness of TMIs. This paper will present three visualizations that have directly resulted in the development of analyses for TMIs or lead to insights into air traffic operations.
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Summary

When operationally significant weather affects a region of the National Airspace System (NAS) a Severe Weather Avoidance Program (SWAP) is initiated for that region. Each SWAP event is a unique mix of demand, weather conditions, traffic flow management (TFM) initiatives and traffic movement. On the day following a SWAP, the...

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Route availability planning tool evaluation vizualizations for the New York and Chigaco departure flows

Creating a cyber moving target for critical infrastructure applications

March 19, 2011
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Conference Paper
Author:
Hamed Okhravi
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Published in:
5th IFIP Int. Conf. on Critical Infrastructure Protection, ICCIP 2011, 19-21 March 2011.
Topic:
systems architecture
R&D area:
R&D group:

Summary

Despite the significant amount of effort that often goes into securing critical infrastructure assets, many systems remain vulnerable to advanced, targeted cyber attacks. This paper describes the design and implementation of the Trusted Dynamic Logical Heterogeneity System (TALENT), a framework for live-migrating critical infrastructure applications across heterogeneous platforms. TALENT permits a running critical application to change its hardware platform and operating system, thus providing cyber survivability through platform diversity. TALENT uses containers (operating-system-level virtualization) and a portable checkpoint compiler to create a virtual execution environment and to migrate a running application across different platforms while preserving the state of the application (execution state, open files and network connections). TALENT is designed to support general applications written in the C programming language. By changing the platform on-the-fly, TALENT creates a cyber moving target and significantly raises the bar for a successful attack against a critical application. Experiments demonstrate that a complete migration can be completed within about one second.
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Summary

Despite the significant amount of effort that often goes into securing critical infrastructure assets, many systems remain vulnerable to advanced, targeted cyber attacks. This paper describes the design and implementation of the Trusted Dynamic Logical Heterogeneity System (TALENT), a framework for live-migrating critical infrastructure applications across heterogeneous platforms. TALENT permits...

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Creating a cyber moving target for critical infrastructure applications

Bioinspired resource management for multiple-sensor target tracking systems

March 7, 2011
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Conference Paper
Author:
Hendrick C. Lambert
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Published in:
2011 IEEE Aerospace Conf., 5-12 March 2011.
Topic:
sensors
R&D area:
R&D group:

Summary

We present an algorithm, inspired by self-organization and stigmergy observed in biological swarms, for managing multiple sensors tracking large numbers of targets. We devise a decentralized architecture wherein autonomous sensors manage their own data collection resources and task themselves. Sensors cannot communicate with each other directly; however, a global track file, which is continuously broadcast, allows the sensors to infer their contributions to the global estimation of target states. Sensors can transmit their data (either as raw measurements or some compressed format) only to a central processor where their data are combined to update the global track file. We outline information-theoretic rules for the general multiple-sensor Bayesian target tracking problem. We provide specific formulas for problems dominated by additive white Gaussiannoise. Using Cramer-Rao lower bounds as surrogates for error covariances, we illustrate, using numerical scenarious involving ballistic targets, that the bioinspired algorithm is highly scalable and peforms very well for large numbers of targets.
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Summary

We present an algorithm, inspired by self-organization and stigmergy observed in biological swarms, for managing multiple sensors tracking large numbers of targets. We devise a decentralized architecture wherein autonomous sensors manage their own data collection resources and task themselves. Sensors cannot communicate with each other directly; however, a global track...

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Bioinspired resource management for multiple-sensor target tracking systems

Measurement of the absolute Raman scattering cross sections of sulfur and the standoff Raman detection of a 6-mm-thick sulfur specimen at 1500m

March 1, 2011
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Journal Article
Author:
Roshan L. Aggarwal
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Published in:
J. Raman Spectr., Vol. 42, No. 3, March 2011, pp. 461-464.
Topic:
detection systems
R&D area:
R&D group:

Summary

The absolute Raman scattering cross sections (σRS) for the 471, 217, and 153 cm−1 modes of sulfur were measured as 6.0 ± 1.2 × 10−27, 7.7 ± 1.6 × 10−27, and 1.2 ± 0.24 × 10−26 cm2 at 815, 799, and 794 nm, respectively, using a 785-nm pump laser. The corresponding values of σRS at 1120, 1089, and 1081 nm were determined to be 1.5 ± 0.3 × 10−27, 1.2 ± 0.24 × 10−27, and 1.2 ± 0.24 × 10−27 cm2 using a 1064-nm laser. A temperature-controlled, small-cavity (2.125 mm diameter) blackbody source was used to calibrate the signal output of the Raman spectrometers for these measurements. Standoff Raman detection of a 6-mm-thick sulfur specimen located at 1500 m from the pump laser and the Raman spectrometer was made using a 1.4-W, CW, 785-nm pump laser.
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Summary

The absolute Raman scattering cross sections (σRS) for the 471, 217, and 153 cm−1 modes of sulfur were measured as 6.0 ± 1.2 × 10−27, 7.7 ± 1.6 × 10−27, and 1.2 ± 0.24 × 10−26 cm2 at 815, 799, and 794 nm, respectively, using a 785-nm pump laser. The...

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Measurement of the absolute Raman scattering cross sections of sulfur and the standoff Raman detection of a 6-mm-thick sulfur specimen at 1500m

Work-function-tuned TiN metal gate FDSOI transistors for subthreshold operation

February 1, 2011
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Journal Article
Author:
Steven A. Vitale
…
Published in:
IEEE Trans. Electron Devices, Vol. 58, No. 2, February 2011, pp. 419-426.
R&D area:

Summary

The effective work function of a reactively sputtered TiN metal gate is shown to be tunable from 4.30 to 4.65 eV. The effective work function decreases with nitrogen flow during reactive sputter deposition. Nitrogen annealing increases the effective work function and reduces Dit. Thinner TiN improves the variation in effective work function and reduces gate dielectric charge. Doping of the polysilicon above the TiN metal gate with B or P has negligible effect on the effective work function. The work-function-tuned TiN is integrated into ultralow-power fully depleted silicon-on-insulator CMOS transistors optimized for subthreshold operation at 0.3 V. The following performance metrics are achieved: 64-80-mV/dec subthreshold swing, PMOS/NMOS on-current ratio near 1, 71% reduction inCgd, and 55% reduction in Vt variation when compared with conventional transistors, although significant short-channel effects are observed.
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Summary

The effective work function of a reactively sputtered TiN metal gate is shown to be tunable from 4.30 to 4.65 eV. The effective work function decreases with nitrogen flow during reactive sputter deposition. Nitrogen annealing increases the effective work function and reduces Dit. Thinner TiN improves the variation in effective...

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Work-function-tuned TiN metal gate FDSOI transistors for subthreshold operation
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