The Effect of Fixed Charge in Tunnel-Barrier Contacts for Fermi-Level Depinning in Germanium

Roy, Arunanshu M.; Lin, Jiunn-Yuan; Saraswat, Krishna C.

doi:10.1109/led.2012.2191386

Cited by 13 publications

(15 citation statements)

References 12 publications

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“…In semiconductor/metal junctions, a similar effect has been reported that the contact resistance of the junctions is considerably reduced by inserting a thin-insulating layer between the semiconductor and metal layer, where the insulating layer has thickness of lower than ∼2 nm (refs 17 , 18 ). In this geometry, the electron introduced in the metal electrode must be injected to the mobile bands of the semiconductor by quantum mechanical tunnelling effect, and then this type of contact is referred to as ‘tunnel contact' or ‘tunnel-barrier contact'.…”

Section: Resultsmentioning

confidence: 62%

Direct electron injection into an oxide insulator using a cathode buffer layer

Lee

Kim

et al. 2015

Nat Commun

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Injecting charge carriers into the mobile bands of an inorganic oxide insulator (for example, SiO2, HfO2) is a highly complicated task, or even impossible without external energy sources such as photons. This is because oxide insulators exhibit very low electron affinity and high ionization energy levels. Here we show that a ZnO layer acting as a cathode buffer layer permits direct electron injection into the conduction bands of various oxide insulators (for example, SiO2, Ta2O5, HfO2, Al2O3) from a metal cathode. Studies of current–voltage characteristics reveal that the current ohmically passes through the ZnO/oxide-insulator interface. Our findings suggests that the oxide insulators could be used for simply fabricated, transparent and highly stable electronic valves. With this strategy, we demonstrate an electrostatic discharging diode that uses 100-nm SiO2 as an active layer exhibiting an on/off ratio of ∼107, and protects the ZnO thin-film transistors from high electrical stresses.

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Section: Resultsmentioning

confidence: 62%

Direct electron injection into an oxide insulator using a cathode buffer layer

Lee

Kim

et al. 2015

Nat Commun

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“…In the presence of fixed charges, a plot of the flat-band voltage against the insulator thickness could exhibit a straight line, in which case the slope gives the density of the fixed charge residing at the insulator-semiconductor interface, or the plot could exhibit a curve, in which case the slope extrapolated to zero thickness would give the amount of interface fixed charge and the curvature indicates the density of charge residing inside the insulator. For the present discussion involving very thin interlayers, the distinction between the two types of fixed charge is unnecessary and one can simply assume an areal density of (positive) fixed charge, en f xch , to reside at the I-S interface, 330,331 from which the following zero-bias n-type SBH for the MIS stack can be derived …”

Section: B Sbh Modification With Thin Layer Of Insulating Materialsmentioning

confidence: 99%

The physics and chemistry of the Schottky barrier height

Tung

2014

Applied Physics Reviews

1,039

479

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The formation of the Schottky barrier height (SBH) is a complex problem because of the dependence of the SBH on the atomic structure of the metal-semiconductor (MS) interface. Existing models of the SBH are too simple to realistically treat the chemistry exhibited at MS interfaces. This article points out, through examination of available experimental and theoretical results, that a comprehensive, quantum-mechanics-based picture of SBH formation can already be constructed, although no simple equations can emerge, which are applicable for all MS interfaces. Important concepts and principles in physics and chemistry that govern the formation of the SBH are described in detail, from which the experimental and theoretical results for individual MS interfaces can be understood. Strategies used and results obtained from recent investigations to systematically modify the SBH are also examined from the perspective of the physical and chemical principles of the MS interface.

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“…The technique was also demonstrated on III-V semiconductors by Hu et al 15 The presence of fixed charges within interlayers has also been proposed to explain reduced contact resistance. 16 In separate studies, reductions in metal/interlayer/semiconductor (MIS) contact resistance have been reported on n-type and p-type 10 15 cm À3 doped Si substrates. Coss et al 17 used TaN electrodes and explained the improvement in contact resistance to p-type Si in terms of AlO x /SiO 2 dipoles.…”

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confidence: 99%