Stability conditions, nonlinear dynamics, and thermal runaway in microbolometers

Brandão, G. B.; Almeida, L.A.L. de; Deep, G.S.; Lima, A.M.N.; Neff, H.

doi:10.1063/1.1384852

Cited by 16 publications

(6 citation statements)

References 11 publications

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“…Both parameters are 3 to 5 orders of magnitude smaller than previously observed for a Gethermistor in [12]. This observation is consistent with an apparently very small volume.…”

Section: Resultssupporting

confidence: 89%

“…In other words, the formation of and propagation in filamentary conduction channels also can be considered as result of the thermo-physical conditions during breakdown. As was outlined in [12], the thermophysical parameters vary weakly with temperature, as do carrier mobility and electronic band-gap of the insulator. In this study, this effect has not been considered, due to lack of reliable experimental data.…”

Section: Resultsmentioning

confidence: 94%

“…For details of the mathematical treatment of strong positive electro-thermal feedback and existence of current and temperature singularities in materials with negative TCR, we refer to [12].…”

Section: Electro-thermal Instabilitymentioning

confidence: 99%

“…Due to the denominator in (7), the differential equation becomes non-linear, which excludes an analytical solution. With the approximation R Ins 0 = (1 + β(∆T ), and β being independent of temperature, (7) can be linearized and solved analytically, as shown earlier in [12]. The critical voltage for thermal run-away then writes as…”

Section: Electro-thermal Instabilitymentioning

confidence: 99%

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Refined dielectric breakdown model for crystalline organic insulators: Electro-thermal instability coupled to interband impact ionization

Lima

Neto

Neff

et al. 2010

2010 IEEE International Power Modulator and High Voltage Conference

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A refined, substantially improved dielectric breakdown model is presented and applied to solution grown, single crystalline alkane type polymeric (n-C36H74) insulator, representing the iso-electronic analog to polyethylene. Illumination of attached electrodes allows controlled generation, injection into and transport of free charge carriers through the insulator. At sufficiently high electric fields, carrier transport is mediated by delocalized states in the conduction and valence band, respectively. At low and moderate fields, charge transport is suppressed by carrier trapping effects. Electric field induced inter-band impact ionization and generation of electron-hole pairs has been identified from these experiments as the dominant carrier multiplication and breakdown triggering mechanism. Critical field magnitudes > 1.26MV/cm have been recorded for injected electrons and > 0.8MV/cm for defect electrons. Application of the energy conservation principle, in accord with the solid state band model, allows determination of critical fields from the insulators electronic band-gap, effective mass and mobility of minority charge carriers. The related electrical breakdown feature and associated rapid dynamic temperature evolution has been explored on basis of the electro-thermal heat balance equation, following previous concepts applied to phase transitions. The non-linear differential equation has been solved numerically, using appropriate thermo-physical materials parameters, while considering the dielectric breakdown phenomenon as a singularity of the solution. Thermal and current run-away is due to strong positive electro-thermal feedback, in connection with an initial transient resistive behavior. Very small thermo-physical parameters are attributed to and explain filamentary charge transport. The temporal evolution of temperature and current in the conducting section or filament during the breakdown event exhibits a time scale up to the microsecond range. Shock wave emission is apparent, since the spatial temperature propagation exceeds the velocity of sound.

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“…Both parameters are 3 to 5 orders of magnitude smaller than previously observed for a Gethermistor in [12]. This observation is consistent with an apparently very small volume.…”

Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 94%

Section: Electro-thermal Instabilitymentioning

confidence: 99%

Section: Electro-thermal Instabilitymentioning

confidence: 99%

See 2 more Smart Citations

Refined dielectric breakdown model for crystalline organic insulators: Electro-thermal instability coupled to interband impact ionization

Lima

Neto

Neff

et al. 2010

2010 IEEE International Power Modulator and High Voltage Conference

Self Cite

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“…Details regarding bias dependent dynamics of bolometer operation are presented elsewhere. 9 The hysteretic temperature induced resistance variation R͑T͒ of a VO 2 − film, having a negative TCR, can be written as R͑T͒ = 17 expͩ 2553…”

mentioning

confidence: 99%

Modeling and performance of vanadium–oxide transition edge microbolometers

Almeida

Deep

Lima

et al. 2004

Applied Physics Letters

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The performance of a VO 2 thin-film microbolometer has been investigated. The device is operated within 35°C Ͻ T Ͻ 60°C, in the hysteretic metal-insulator transition region. An algebraic hysteresis model has been used to model the resistance-temperature characteristic of the sensor. It accurately describes the resistance versus temperature characteristics of the material. Employing this model, and in conjunction with established bolometer theory, the responsivity of a VO 2 film is calculated and compared with experimental data. Superior performance of the device is achievable under conditions of single pulse incident radiation where the operating point remains on the major hysteresis loop. This results in a pronounced responsivity peak within the center of the metal-insulator transition. Continuous periodic excitation, in contrast, leads to a steadily decreasing and much lower sensitivity at higher temperature, due to the formation of minor hysteresis loops and the loop accommodation process.

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