Mr. Philip Ely Profile

Philip Ely

Director of Engineering at Leonardo DRS

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Publications (5)

Proceedings Article | 2 May 2016 Paper

Detectors and focal plane modules for weather satellites

A. D'Souza, E. Robinson, S. Masterjohn, P. Ely, V. Khalap, S. Babu, D. Smith

Proceedings Volume 9881, 988115 (2016) https://doi.org/10.1117/12.2228898

KEYWORDS: Sensors, Mid-IR, Long wavelength infrared, Visible radiation, Short wave infrared radiation, Quantum efficiency, Photodiodes, Staring arrays, Readout integrated circuits, Silicon

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Weather satellite instruments require detectors with a variety of wavelengths ranging from the visible to VLWIR. One of the remote sensing applications is the geostationary GOES-ABI imager covering wavelengths from the 450 to 490 nm band through the 13.0 to 13.6 μm band. There are a total of 16 spectral bands covered. The Cross-track infrared Sounder (CrIS) is a Polar Orbiting interferometric sensor that measures earth radiances at high spectral resolution, using the data to provide pressure, temperature and moisture profiles of the atmosphere. The pressure, temperature and moisture sounding data are used in weather prediction models that track storms, predict levels of precipitation etc. The CrIS instrument contains SWIR (λ_c ∼ 5 μm at 98K), MWIR (λ_c ∼ 9 μm at 98K) and LWIRs (λ_c ∼ 15.5 μm at 81K) bands in three Focal Plane Array Assemblies (FPAAs).

GOES-ABI contains three focal plane modules (FPMs), (i) a visible-near infrared module consisting of three visible and three near infrared channels, (ii) a MWIR module comprised of five channels from 3.9 μm to 8.6 μm and (iii) a 9.6 μm to 13.3 μm, five-channel LWIR module. The VNIR FPM operates at 205 K, and the MWIR and LWIR FPMs operate at 60 K. Each spectral channel has a redundant array built into a single detector chip. Switching is thus permitted from the primary selected array in each channel to the redundant array, given any degradation in performance of the primary array during the course of the mission. Silicon p-i-n detectors are used for the 0.47 μm to 0.86 μm channels. The thirteen channels above 1 μm are fabricated in various compositions of Hg_1-xCd_xTe, and in this particular case using two different detector architectures. The 1.38 μm to 9.61 μm channels are all fabricated in Hg_1-xCd_xTe grown by Liquid Phase Epitaxy (LPE) using the HDVIP detector architecture. Molecular beam epitaxy (MBE)-grown Hg_1-xCd_xTe material are used for the LWIR 10.35 μm to 13.3 μm channels fabricated in Double layer planar heterostructure (DLPH) detectors. This is the same architecture used for the CrIS detectors.

CrIS detectors are 850 μm diameter detectors with each FPAA consisting of nine photovoltaic detectors arranged in a 3 x 3 pattern. Each detector has an accompanying cold preamplifier. SWIR and MWIR FPAAs operate at 98 K and the LWIR FPAA at 81 K, permitting the use of passive radiators to cool the detectors. D* requirements at peak wavelength are ≥ 5.0E+10 Jones for LWIR, ≥ 9.3E+10 Jones for MWIR and ≥ 3.0E+11 Jones for SWIR. All FPAAs exceeded the D* requirements. Measured mean values for the nine photodiodes in each of the LWIR, MWIR and SWIR FPAAs are D* = 5.3 x 10¹⁰ cm-Hz^1/2/W at 14.0 μm, 1.0 x 10¹¹ cm-Hz^1/2/W at 8.0 μm and 3.1 x 10¹¹ cm-Hz^1/2/W at 4.64 μm.

Proceedings Article | 15 October 2012 Paper

Silicon [i]pin[/i] diodes for remote sensing

Ernest Robinson, Arvind D'Souza, Phil Ely, Craig Yoneyama

Proceedings Volume 8512, 85120Q (2012) https://doi.org/10.1117/12.970311

KEYWORDS: Sensors, Quantum efficiency, Silicon, Modulation transfer functions, Diodes, Staring arrays, PIN photodiodes, Charge-coupled devices, Camera shutters, Infrared sensors

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Proceedings Article | 4 May 2010 Paper

SWIR HgCdTe HDVIP detectors MTF Monte Carlo modeling and data

A. D'Souza, M. Stapelbroek, C. Yoneyama, P. Ely, M. Skokan, H. Shih

Proceedings Volume 7660, 76600Q (2010) https://doi.org/10.1117/12.849554

KEYWORDS: Sensors, Modulation transfer functions, Monte Carlo methods, Data modeling, Mercury cadmium telluride, Diffusion, Fourier transforms, Short wave infrared radiation, Photons, Metals

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Proceedings Article | 18 May 2006 Paper

SWIR to LWIR HDVIP HgCdTe detector array performance

A. D'Souza, M. Stapelbroek, L. Dawson, P. Ely, C. Yoneyama, J. Reekstin, M. Skokan, M. Kinch, P. Liao, M. Ohlson, P. Ronci, T. Teherani, H. Shih, J. Robinson

Proceedings Volume 6206, 62062H (2006) https://doi.org/10.1117/12.669071

KEYWORDS: Sensors, Long wavelength infrared, Readout integrated circuits, Short wave infrared radiation, Mercury cadmium telluride, Quantum efficiency, Detector arrays, Mid-IR, Staring arrays, Diodes

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DRS uses LPE-grown SWIR, MWIR and LWIR HgCdTe material to fabricate High-Density Vertically Integrated Photodiode (HDVIP) architecture detectors. 2.5 μm, 5.3 μm and 10.5 μm cutoff detectors have been fabricated into linear arrays as technology demonstrations targeting remote sensing programs. This paper presents 320 x 6 array configuration technology demonstrations' performance of HDVIP HgCdTe detectors and single detector noise data. The single detector data are acquired from within the 320 x 6 array. Within the arrays, the detector size is 40 μm x 50 μm. The MWIR detector array has a mean quantum efficiency of 89.2% with a standard deviation to mean ratio, σ/μ = 1.51%. The integration time for the focal plane array (FPA) measurements is 1.76 ms with a frame rate of 557.7 Hz. Operability values exceeding 99.5% have been obtained. The LWIR arrays measured at 60 K had high operability with only ~ 3% of the detectors having out of family response. Using the best detector select (BDS) feature in the read out integrated circuit (ROIC), a feature that picks out the best detector in every row of six detectors, a 320 x 1 array with 100% operability is obtained. For the 320 x 1 array constituted using the BDS feature, a 100% operable LWIR array with average NEI value of 1.94 x 10¹¹ ph/cm²/s at a flux of 7.0 x 10¹⁴ ph/cm²/s has been demonstrated. Noise was measured at 60 K and 50 mV reverse bias on a column of 320 diodes from a 320 x 6 LWIR array. Integration time for the measurement was 1.76 ms. Output voltage for the detectors was sampled every 100^th frame. 32,768 frames of time series data were collected for a total record length of 98 minutes. The frame average for a number of detectors was subtracted from each detector to correct for temperature drift and any common-mode noise. The corrected time series data was Fourier transformed to obtain the noise spectral density as a function of frequency. Since the total time for collecting the 32,768 time data series points is 98.0 minutes, the minimum frequency is 170 μHz. A least squares fit of the form (A/f + B) is made to the noise spectral density data to extract coefficients A and B that relate to the 1/f and white noise of the detector respectively. In addition noise measurements were also acquired on columns of SWIR detectors. Measurements were made under illuminated conditions at 4 mV and 50 mV reverse bias and under dark conditions at 50 mV reverse bias. The total collection time for the SWIR detectors was 47.7 minutes. The detectors are white noise limited down to ~10 mHz under dark conditions and down to ~ 100 mHz under illuminated conditions.

Proceedings Article | 21 October 2005 Paper

SWIR to LWIR HgCdTe detectors and FPAs for remote sensing applications

A. D'Souza, M. Stapelbroek, L. Dawson, P. Ely, C. Yoneyama, J. Reekstin, H.-D. Shih, M. Skokan, T. Teherani, J. Robinson

Proceedings Volume 5978, 597818 (2005) https://doi.org/10.1117/12.627752

KEYWORDS: Sensors, Long wavelength infrared, Quantum efficiency, Readout integrated circuits, Remote sensing, Diodes, Mercury cadmium telluride, Mid-IR, Detector arrays, Short wave infrared radiation

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