Characterization of (Hg,Cd)Te by the photoconductive decay technique

Lopes, V. C.; Wright, W. H.; Syllaios, A. J.

doi:10.1116/1.576937

Cited by 21 publications

(7 citation statements)

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“…The parameters used to fit the model calculations to the experimental data are presented in table 2. For comparison, the values for interface trap density [4,[11][12][13] and capture coefficients for surface traps [12] are typically those found by others for the HgCdTe/anodic oxide interface. From figure 6 it is evident that a simple MIS model is able to account for the observed behaviour, and that there is reasonable agreement with the measured data.…”

Section: Resultsmentioning

confidence: 79%

“…The gate metal used was indium which was thin enough (i.e. 30 nm) to be essentially transparent to long-wavelength radiation, 1×10 12 cm −2 eV −1 Mobility of surface charge (µ s ) 4×10 4 cm 2 V −1 s −1 Capture cross-section (σ ) 2×10 −11 cm 2 which was confirmed by FTIR measurements. All device measurements were taken at 80 K. From capacitancevoltage measurements on the MIS structure, a flat-band voltage of −12.5 V was obtained.…”

Section: Resultsmentioning

confidence: 83%

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A gate-controlled HgCdTe long-wavelength infrared photoconductive detector

Siliquini

Faraone

1997

Semicond. Sci. Technol.

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A gated photoconductor structure is proposed for the dual purpose of enhancing the performance of and investigating surface effects in HgCdTe photoconductive infrared detectors. It is verified both theoretically and experimentally that the passivating native oxide which accumulates the HgCdTe surface, thereby quenching surface recombination, also causes excessive surface shunting and an overall reduction in device responsivity. It is found that for x = 0.23 Hg 1−x Cd x Te photoconductive detectors passivated with native oxide/ZnS the optimum surface conditions prevail at a gate bias corresponding to a semiconductor surface potential of 50 mV. Experimentally, it is found that operation at this optimum condition yields approximately a 70% increase in responsivity in comparison to floating gate conditions, which corresponds to a surface potential of 72 mV for the as-grown native oxide/HgCdTe interface. The gated photoconductor is shown to be a powerful diagnostic device structure that can be used to evaluate and optimize surface passivation layers for HgCdTe infrared detectors.

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Section: Resultsmentioning

confidence: 79%

Section: Resultsmentioning

confidence: 83%

A gate-controlled HgCdTe long-wavelength infrared photoconductive detector

Siliquini

Faraone

1997

Semicond. Sci. Technol.

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“…At high indium concentration, In incorporates as a neutral complex corresponding to In 2 Te 3 . Figures 4 and 5 show the data of the measured carrier lifetime at 80 K for n-type HgCdTe materials with a different carrier concentrations, collected by Lopes et al 47 The data include the experimental results of various researchers 48 for In-doped n-type bulk crystals and epilayers LWIR (Fig. 4) and MWIR (Fig.…”

Section: A N-type Materialsmentioning

confidence: 98%

The bulk generation-recombination processes and the carrier lifetime in mid-wave infrared and long-wave infrared liquid nitrogen cooled HgCdTe alloys

Jóźwikowski

Kopytko

Rogalski

2012

Journal of Applied Physics

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Comprehensive study of the bulk generation-recombination mechanisms and the carrier lifetime in long wavelength and mid wavelength infrared indium-doped as well as arsenic- and mercury vacancies-doped HgCdTe ternary alloys at liquid nitrogen temperature has been done. The excess minority carrier lifetime in HgCdTe materials has been calculated by solving the set of non-linear transport equations under conditions of small deviation from equilibrium. The results of numerical calculations of the carrier lifetime determined by the Auger 1, Auger 7, and Shockley-Read-Hall mechanisms related to mercury vacancies have been compared with experimental data available in the literature. We re-examine the carrier lifetime, including the impact of the electrical screening on Coulomb interaction of carriers in the Auger process to explain certain inconsistency between theoretical prediction and experimental data especially in highly doped p-type HgCdTe material. Moreover, the marginal significance of the interband radiative recombination has been indicated.

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“…To study the thermal stability of the fabricated devices photoconductive decay was measured both before and after baking to allow the extraction of bulk semiconductor lifetime and the surface recombination velocity [11]. When performing photoconductive lifetime measurements on devices in which there is significant surface recombination, the decay is composed of two exponential lifetimes; one dependent on the bulk lifetime, the other on the surface recombination velocity.…”

Section: Lwir Thermal Stability Measurementsmentioning

confidence: 99%

Thermal Stability in HgCdTe IR Photodiodes

et al. 2002

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Packaging of HgCdTe photodiode detector arrays in a dewar involves degassing at elevated temperatures for several days so as to achieve vacuum integrity. This sustained exposure to relatively high temperatures can influence the HgCdTe bulk material properties, p-n junction integrity, and the passivant-HgCdTe interface. This work investigates the effects of bake-out treatment on the performance of HgCdTe based photodiodes formed using a new plasma induced type conversion process. Experimental results of a series of experiments in both long-wavelength infrared (LWIR) and mid-wavelength infrared (MWIR) devices are presented.Bulk lifetime was used as an indicator of the change in the bulk material resulting from baking in vacuum and was measured by photoconductive decay. These measurements did not show any appreciable changes as a result of baking. Modification of the doping profile in the n-p junction may also result from high temperature baking. Doping profiles of the photodiodes were studied by measuring the junction capacitance-voltage relation before and after baking. The results of these tests after baking showed no changes to C-V measurements from those before bake.The effect of baking on the passivant/HgCdTe interface was also examined by carrying out surface recombination velocity measurements by photoconductive decay on samples with different passivation layers.Variable area HgCdTe photodiodes have also been fabricated and studied to understand the effect of the surface condition of the performance of the devices. Initial bake tests on LWIR devices show that the technology is stable when employing a double layer passivation technique. Bake tests on the more advanced MWIR technology indicates that the plasma induced type conversion process produces stable photodiodes with state of the art performance.

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Characterization of (Hg,Cd)Te by the photoconductive decay technique

Cited by 21 publications

References 0 publications

A gate-controlled HgCdTe long-wavelength infrared photoconductive detector

A gate-controlled HgCdTe long-wavelength infrared photoconductive detector

The bulk generation-recombination processes and the carrier lifetime in mid-wave infrared and long-wave infrared liquid nitrogen cooled HgCdTe alloys

Thermal Stability in HgCdTe IR Photodiodes

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