The electrical characterization and response to hydrogen of Schottky diodes with a resistive metal electrode—rectifying an oversight in Schottky diode investigation

Dawson, Paul; Feng, Lei; Penate-Quesada, Laura; Mitra, Joy; Hill, G.

doi:10.1088/0022-3727/44/12/125101

Cited by 3 publications

(2 citation statements)

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“…Here, results from Pt/p-Si and Pd/p-Si devices are analyzed in detail, while we have reported a less in-depth survey of a broader range of Schottky contacts using this methodology elsewhere. 45 In the results discussed below, the metal electrode resistance lies in the range of 0.2-40 kX.…”

Section: Introductionmentioning

confidence: 96%

An alternative methodology in Schottky diode physics

Mitra

Feng

Penate-Quesada³

et al. 2015

Journal of Applied Physics

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The fabrication and electrical characterization of Schottky junction diodes have been extensively researched for three-quarters of a century since the original work of Schottky in 1938. This study breaks from the highly standardized regime of such research and provides an alternative methodology that prompts novel, more efficient applications of the adroit Schottky junction in areas such as chemical and thermal sensing. The core departure from standard Schottky diode configuration is that the metal electrode is of comparable or higher resistance than the underlying semiconductor. Further, complete electrical characterization is accomplished through recording four-probe resistance-temperature (R D -T) characteristics of the device, where electrical sourcing and sensing is done only via the metal electrode and not directly through the semiconductor. Importantly, this results in probing a nominally unbiased junction while eliminating the need for an Ohmic contact to the semiconductor. The characteristic R D -T plot shows two distinct regions of high (metal) and low (semiconductor) resistances at low and high temperatures, respectively, connected by a crossover region of width, DT, within which there is a large negative temperature coefficient of resistance. The R D -T characteristic is highly sensitive to the Schottky barrier height; consequently, at a fixed temperature, R D responds appreciably to small changes in barrier height such as that induced by absorption of a chemical species (e.g., H 2 ) at the interface. A theoretical model is developed to simulate the R D -T data and applied to Pd/p-Si and Pt/p-Si Schottky diodes with a range of metal electrode resistance. The analysis gives near-perfect fits to the experimental R D -T characteristics, yielding the junction properties as fit parameters. The modelling not only helps elucidate the underlying physics but also helps to comprehend the parameter space essential for the discussed applications. Although the primary regime of application is limited to a relatively narrow range (DT) for a given type of diode, the alternative methodology is of universal applicability to all metalsemiconductor combinations forming Schottky contacts. V C 2015 AIP Publishing LLC.

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Section: Introductionmentioning

confidence: 96%

An alternative methodology in Schottky diode physics

Mitra

Feng

Penate-Quesada³

et al. 2015

Journal of Applied Physics

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“…The key feature here, and the crucial departure from conventional Schottky diode fabrication methodology, is that the very thin (<10 nm), elongated metal (Pd) electrode has a resistance that is greater than, or at least comparable to, the underlying InP substrate around room temperature. It is useful to first explain the device properties in terms of the R D -temperature behaviour (we have outlined this behaviour in relation to a variety of silicon-and III-V based Schottky devices [17] and will develop it more fully elsewhere [18]). In this scheme R D undergoes a significant drop from high values at low temperature, where the charge carriers are confined to the resistive metal electrode, to low values at high temperature, where the semiconductor substrate has opened up as a parallel current carrying channel.…”

mentioning

confidence: 99%

High sensitivity (1 ppm) hydrogen detection using an unconventional Pd/n-InP Schottky device

Feng¹,

Mitra²,

Dawson³

et al. 2011

J. Phys.: Condens. Matter

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Hydrogen is detected using a Pd/n-InP Schottky diode in which the elongated, very thin Pd electrode is of greater resistance than the underlying semiconductor substrate. Four-probe measurements of the device resistance, as a function of hydrogen concentration, are made by contacting only the Pd electrode, with a sensitivity of 1 ppm being achieved. On hydrogen exposure the device resistance drops from an initial high value, characteristic of the Pd electrode alone, to a lower value due to a hydrogen-induced lowering of the Schottky barrier that opens up the InP substrate as a parallel current carrying channel.

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