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A 4-side tileable back illuminated 3D-integrated Mpixel CMOS image sensor

Summary

The dominant trend with conventional image sensors is toward scaled-down pixel sizes to increase spatial resolution and decrease chip size and cost. While highly capable chips, these monolithic image sensors devote substantial perimeter area to signal acquisition and control circuitry and trade off pixel complexity for fill factor. For applications such as wide-area persistent surveillance, reconnaissance, and astronomical sky surveys it is desirable to have simultaneous near-real-time imagery with fast, wide field-of-view coverage. Since the fabrication of a complex large-format sensor on a single piece of silicon is cost and yield-prohibitive and is limited to the wafer size, for these applications many smaller-sized image sensors are tiled together to realize very large arrays. Ideally the tiled image sensor has no missing pixels and the pixel pitch is continuous across the seam to minimize loss of information content. CCD-based imagers have been favored for these large mosaic arrays because of their low noise and high sensitivity, but CMOS-based image sensors bring architectural benefits, including electronic shutters, enhanced radiation tolerance, and higher data-rate digital outputs that are more easily scalable to larger arrays. In this report the first back-illuminated, 1 Mpixel, 3D-integrated CMOS image sensor with 8 mum-pitch 3D via connections. The chip employs a conventional pixel layout and requires 500 mum of perimeter silicon to house the support circuitry and protect the array from saw damage. In this paper we present a back-illuminated 1 Mpixel CMOS image sensor tile that includes a 64-channel vertically integrated ADC chip stack, and requires only a few pixels of silicon perimeter to the pixel array. The tile and system connector design support 4-side abuttability and fast burst data rates.
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Summary

The dominant trend with conventional image sensors is toward scaled-down pixel sizes to increase spatial resolution and decrease chip size and cost. While highly capable chips, these monolithic image sensors devote substantial perimeter area to signal acquisition and control circuitry and trade off pixel complexity for fill factor. For applications...

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High-quality 150 nm InP-to-silicon epitaxial transfer for silicon photonic integrated circuits

Published in:
Electrochem. Solid-State Lett., Vol. 12, No. 4, January 2009, pp. H101-H104.

Summary

We demonstrate the transfer of the largest (150 mm in diameter) available InP-based epitaxial structure to the silicon-on-insulator substrate through a direct wafer-bonding process. Over 95% bonding yield and a void-free bonding interface was obtained. A multiple quantum-well diode laser structure is well-preserved after bonding, as indicated by the high-resolution X-ray diffraction measurement and photoluminescence (PL) map. A bowing of 64.12 um is measured, resulting in a low bonding-induced strain of 17 MPa. PL measurement shows a standard deviation of 1.09% across the entire bonded area with less than 1.1 nm wavelength shift from the as-grown wafer.
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Summary

We demonstrate the transfer of the largest (150 mm in diameter) available InP-based epitaxial structure to the silicon-on-insulator substrate through a direct wafer-bonding process. Over 95% bonding yield and a void-free bonding interface was obtained. A multiple quantum-well diode laser structure is well-preserved after bonding, as indicated by the high-resolution...

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A novel method for remotely detecting trace explosives

Published in:
Lincoln Laboratory Journal, Vol. 17, No. 2, December 2008, pp. 27-40.

Summary

The development of a technique with the ability to detect trace quantities of explosives at a distance is of critical importance. In numerous situations when explosive devices are prepared, transported, or otherwise handled, quantifiable amounts of the explosive material end up on surfaces. Rapid detection of these chemical residues in a noninvasive standoff manner would serve as an indicator for attempts at concealed assembly or transport of explosive materials and devices. We are investigating the use of a fluorescence-based technique to achieve the necessary detection sensitivity.
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Summary

The development of a technique with the ability to detect trace quantities of explosives at a distance is of critical importance. In numerous situations when explosive devices are prepared, transported, or otherwise handled, quantifiable amounts of the explosive material end up on surfaces. Rapid detection of these chemical residues in...

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New methods to transport fluids in micro-sized devices

Published in:
Lincoln Laboratory Journal, Vol. 17, No. 2, December 2008, pp. 70-80.

Summary

Applications of microfluidics require a self-contained, active pumping system in which the package size is comparable to the volume of fluid being transported. Over the past decade, several systems have been developed to address this issue, but either these systems have high power requirements or the microfabrication is too complex to be cost efficient. A recent effort at Lincoln Laboratory using an emerging technology called electrowetting has led to the development of several novel micropump concepts for pumping liquids continuously, as well as for pumping discrete volumes.
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Summary

Applications of microfluidics require a self-contained, active pumping system in which the package size is comparable to the volume of fluid being transported. Over the past decade, several systems have been developed to address this issue, but either these systems have high power requirements or the microfabrication is too complex...

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Detection of condensed-phase explosives via laser-induced vaporization, photodissociation, and resonant excitation

Published in:
Appl. Opt., Vol. 47, No. 31, 1 November 2008, pp. 5767-5776.

Summary

We investigate the remote detection of explosives via a technique that vaporizes and photodissociates the condensed-phase material and detects the resulting vibrationally excited NO fragments via laser-induced fluorescence. The technique utilizes a single 7 ns pulse of a tunable laser near 236:2nm to perform these multiple processes. The resulting blue-shifted fluorescence (226 nm) is detected using a photomultiplier and narrowband filter that strongly block the scatter of the pump laser off the solid media while passing the shorter wavelength photons. Various nitro-bearing compounds, including 2,6-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), and hexahydro-1,3,5- trinitro-1,3,5-triazine (RDX) were detected with a signal-to-noise of 25 dB. The effects of laser fluence, wavelength, and sample morphology were examined.
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Summary

We investigate the remote detection of explosives via a technique that vaporizes and photodissociates the condensed-phase material and detects the resulting vibrationally excited NO fragments via laser-induced fluorescence. The technique utilizes a single 7 ns pulse of a tunable laser near 236:2nm to perform these multiple processes. The resulting blue-shifted...

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Characterization of a three-dimensional SOI integrated-circuit technology

Published in:
2008 IEEE Int. SOI Conf. Proc., 6 October 2008, pp. 109-110.

Summary

At Lincoln Laboratory, we have established a three dimensional (3D) integrated circuit (IC) technology that has been developed and demonstrated over eight designs, bonding two or three active circuit layers or tiers to form monolithically integrated 3D circuits. This technology has been used to successfully demonstrate a large-area 8 x 8 mm2 high-3D-via-count 1024 x 1024 visible image, a 64 x 64 laser radar focal plane based on single-photon-sensitive avalanche photodiodes, and a 10Gb/s/pin low power interconnect for 3DICs. 3DIC technology in our most recently completed 3D multiproject (3DM2) run includes three active fully-depleted-SOI (FDSOI) circuit tiers, eleven interconnect-metal layers, and dense unrestricted 3D vias interconnecting stacked circuit layers, as shown in Figure 1. While we continue our efforts to scale our 3DIC technology and increase 3D via density, we are also working to improve our understanding of 3D integration impact on transistor and process monitor circuits. In this paper, we describe our process and test results after single tier circuit fabrication as well as after three-tier integration, determine impact of 3D vias on ring oscillator performance, and demonstrate functionality of single and multi-tier circuits of varying complexity.
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Summary

At Lincoln Laboratory, we have established a three dimensional (3D) integrated circuit (IC) technology that has been developed and demonstrated over eight designs, bonding two or three active circuit layers or tiers to form monolithically integrated 3D circuits. This technology has been used to successfully demonstrate a large-area 8 x...

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InP-based single-photon detector arrays with asynchronous readout integrated circuits

Summary

We have developed and demonstrated a highduty- cycle asynchronous InGaAsP-based photon counting detector system with near-ideal Poisson response, roomtemperature operation, and nanosecond timing resolution for near-infrared applications. The detector is based on an array of Geiger-mode avalanche photodiodes coupled to a custom integrated circuit that provides for lossless readout via an asynchronous, nongated architecture. We present results showing Poisson response for incident photon flux rates up to 10 million photons per second and multiple photons per 3-ns timing bin.
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Summary

We have developed and demonstrated a highduty- cycle asynchronous InGaAsP-based photon counting detector system with near-ideal Poisson response, roomtemperature operation, and nanosecond timing resolution for near-infrared applications. The detector is based on an array of Geiger-mode avalanche photodiodes coupled to a custom integrated circuit that provides for lossless readout via...

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Amplitude spectroscopy of a solid-state artificial atom

Summary

The energy-level structure of a quantum system, which has a fundamental role in its behaviour, can be observed as discrete lines and features in absorption and emission spectra. Conventionally, spectra are measured using frequency spectroscopy, whereby the frequency of a harmonic electromagnetic driving field is tuned into resonance with a particular separation between energy levels. Although this technique has been successfully employed in a variety of physical systems, including natural and artificial atoms and molecules, its application is not universally straightforward and becomes extremely challenging for frequencies in the range of tens to hundreds of gigahertz. Here we introduce a complementary approach, amplitude spectroscopy, whereby a harmonic driving field sweeps an artificial atom through the avoided crossings between energy levels at a fixed frequency. Spectroscopic information is obtained from the amplitude dependence of the system's response, thereby overcoming many of the limitations of a broadband-frequency-based approach. The resulting 'spectroscopy diamonds', the regions in parameter space where transitions between specific pairs of levels can occur, exhibit interference patterns and population inversion that serve to distinguish the atom's spectrum. Amplitude spectroscopy provides a means of manipulating and characterizing systems over an extremely broad bandwidth, using only a single driving frequency that may be orders of magnitude smaller than the energy scales being probed.
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Summary

The energy-level structure of a quantum system, which has a fundamental role in its behaviour, can be observed as discrete lines and features in absorption and emission spectra. Conventionally, spectra are measured using frequency spectroscopy, whereby the frequency of a harmonic electromagnetic driving field is tuned into resonance with a...

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A 64 x 64-pixel CMOS test chip for the development of large-format ultra-high-speed snapshot imagers

Summary

A 64 x 64-pixel test circuit was designed and fabricated in 0.18- m CMOS technology for investigating high-speed imaging with large-format imagers. Several features are integrated into the circuit architecture to achieve fast exposure times with low-skew and jitter for simultaneous pixel snapshots. These features include an H-tree clock distribution with local and global repeaters, single-edge trigger propagation, local exposure control, and current-steering sampling circuits. To evaluate the circuit performance, test structures are periodically located throughout the 64 x 64-pixel device. Measured devices have exposure times that can be varied between 75 ps to 305 ps with skew times for all pixels less than +-3 ps and jitter that is less than +-1.2 ps rms. Other performance characteristics are a readout noise of approximately 115 e- rms and an upper dynamic range of 310,000 e-.
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Summary

A 64 x 64-pixel test circuit was designed and fabricated in 0.18- m CMOS technology for investigating high-speed imaging with large-format imagers. Several features are integrated into the circuit architecture to achieve fast exposure times with low-skew and jitter for simultaneous pixel snapshots. These features include an H-tree clock distribution...

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High-fidelity quantum operations on superconducting qubits in the presence of noise

Published in:
Phys. Rev. Lett., Vol. 101, No. 7, 15 August 2008, 070501.

Summary

We present a scheme for implementing quantum operations with superconducting qubits. Our approach "coupler" qubit to mediate a controllable interaction between data qubits, pulse sequences which strongly mitigate the effects of 1/f flux noise, and a high-Q resonator-based local memory. We develop a Monte Carlo simulation technique capable of describing arbitrary noise-induced dephasing and decay, and demonstrate in this system a set of universal gate operations with O(10^-5) error probabilities in the presence of experimentally measured levels of 1=f noise. We then add relaxation and quantify the decay times required to maintain this error level.
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Summary

We present a scheme for implementing quantum operations with superconducting qubits. Our approach "coupler" qubit to mediate a controllable interaction between data qubits, pulse sequences which strongly mitigate the effects of 1/f flux noise, and a high-Q resonator-based local memory. We develop a Monte Carlo simulation technique capable of describing...

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