Experimental evidence for the correlation between the weak inversion hump and near midgap states in dielectric/InGaAs interfaces

Applied Physics Letters

Mates

Zhang

et al. 2014

ZrO2 dielectrics were grown on n-In0.53Ga0.47As channels by atomic layer deposition, after employing an in-situ cyclic nitrogen plasma/trimethylaluminum surface cleaning procedure. By scaling the ZrO2 thickness, accumulation capacitance densities of 3.5 μF/cm2 at 1 MHz are achieved. The midgap interface trap density is estimated to be in the 1012 cm−2 eV−1 range. Using x-ray photoelectron spectroscopy, it was shown that the interface contained the oxides of In, Ga, and Al, but no As-oxides or As-As bonds within the detection limit. The results allow for insights into the effective passivation of these interfaces.

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confidence: 52%

“…14,17,18 Deep depletion is reached, as can be seen from the finite slope at negative biases. The large band bending is, of course, facilitated by the high oxide capacitance density.…”

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confidence: 88%

Scaled ZrO2 dielectrics for In0.53Ga0.47As gate stacks with low interface trap densities

Applied Physics Letters

Mates

Zhang

et al. 2014

“…[1][2][3][4][5][6][7][8][9] Interface trap densities (D it ), at least around midgap, are relatively straight-forward to detect for In 0.53 Ga 0.47 As, because of its narrow band gap (0.75 eV (Ref. 10)); they cause, for example, a frequency-dependent hump in the depletion region of capacitance-voltage (CV) characteristics, 11,12 and peaks in normalized conductance maps. 13 Recently, we have reported on an in-situ, cyclic nitrogen plasma/trimethylaluminum (TMA) surface treatment prior to atomic layer deposition (ALD) of gate dielectrics on In 0.53 Ga 0.47 As.…”

Section: Introductionmentioning

confidence: 99%

Influence of plasma-based in-situ surface cleaning procedures on HfO2/In0.53Ga0.47As gate stack properties

Journal of Applied Physics

Mates

Mitchell

et al. 2013

We report on the influence of variations in the process parameters of an in-situ surface cleaning procedure, consisting of alternating cycles of nitrogen plasma and trimethylaluminum dosing, on the interface trap density of highly scaled HfO2 gate dielectrics deposited on n-In0.53Ga0.47As by atomic layer deposition. We discuss the interface chemistry of stacks resulting from the pre-deposition exposure to nitrogen plasma/trimethylaluminum cycles. Measurements of interface trap densities, interface chemistry, and surface morphology show that variations in the cleaning process have a large effect on nucleation and surface coverage, which in turn are crucial for achieving low interface state densities.

“…1(b)] is due to midgap traps. 15,16 In accumulation (i.e., at sufficiently large positive gate bias for n-type channels), however, the semiconductor Fermi level moves deep into the conduction band, due to the low conduction band density of states (DOS) of . The detailed fabrication procedure has been described elsewhere.…”

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confidence: 99%

Frequency dispersion in III-V metal-oxide-semiconductor capacitors

Stemmer

Applied Physics Letters

Rajan

2012

A recombination-controlled tunneling model is used to explain the strong frequency dispersion seen in the accumulation capacitance and conductance of dielectric/n-In0.53Ga0.47As metal-oxide-semiconductor capacitors. In this model, the parallel conductance is large when, at positive gate biases, the metal Fermi level lines up with a large density of interface states in the In0.53Ga0.47As band gap. It is shown that the model explains in a semi-quantitative manner the experimentally observed capacitor characteristics, including a peak in parallel conductance/frequency (Gp/ω) versus log frequency curves at positive gate bias and the dependence of the frequency dispersion on the dielectric thickness.