Challenges and opportunities in atomistic dopant profiling using capacitance-voltage measurements

Aghaei, Samira; Hehta, Mohit; Andrei, Petru; Hagmann, Mark J.

doi:10.1109/asmc.2014.6847009

Cited by 7 publications

(8 citation statements)

References 9 publications

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“…Various methods utilizing the equivalent circuit characteristics can be addressed for accurate determination of the capacitance and the herewith related material and device properties, as reported in previous and recent publications [44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60]. By application of CVM techniques, the capacitance C can be determined from the current in dependence of voltage I(V) characteristics using an equivalent circuit model to evaluate the resistances [46] or alternately fitted to the impedance complex function of a PIN-diode equivalent circuit [44]:…”

Section: Pin-diodes Based On Ingan/gan Dhs With 55% Inmentioning

confidence: 99%

Calibration of Polarization Fields and Electro-Optical Response of Group-III Nitride Based c-Plane Quantum-Well Heterostructures by Application of Electro-Modulation Techniques

Papadimitriou

2019

Applied Sciences

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The polarization fields and electro-optical response of PIN-diodes based on nearly lattice-matched InGaN/GaN and InAlN/GaN double heterostructure quantum wells grown on (0001) sapphire substrates by metalorganic vapor phase epitaxy were experimentally quantified. Dependent on the indium content and the applied voltage, an intense near ultra-violet emission was observed from GaN (with fundamental energy gap Eg = 3.4 eV) in the electroluminescence (EL) spectra of the InGaN/GaN and InAlN/GaN PIN-diodes. In addition, in the electroreflectance (ER) spectra of the GaN barrier structure of InAlN/GaN diodes, the three valence-split bands, Γ9, Γ7+, and Γ7−, could selectively be excited by varying the applied AC voltage, which opens new possibilities for the fine adjustment of UV emission components in deep well/shallow barrier DHS. The internal polarization field Epol = 5.4 ± 1.6 MV/cm extracted from the ER spectra of the In0.21Al0.79N/GaN DHS is in excellent agreement with the literature value of capacitance-voltage measurements (CVM) Epol = 5.1 ± 0.8 MV/cm. The strength and direction of the polarization field Epol = −2.3 ± 0.3 MV/cm of the (0001) In0.055Ga0.945N/GaN DHS determined, under flat-barrier conditions, from the Franz-Keldysh oscillations (FKOs) of the electro-optically modulated field are also in agreement with the CVM results Epol = −1.2 ± 0.4 MV/cm. The (absolute) field strength is accordingly significantly higher than the Epol strength quantified in published literature by FKOs on a semipolar ( 11 2 ¯ 2 ) oriented In0.12Ga0.88N quantum well.

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Section: Pin-diodes Based On Ingan/gan Dhs With 55% Inmentioning

confidence: 99%

Calibration of Polarization Fields and Electro-Optical Response of Group-III Nitride Based c-Plane Quantum-Well Heterostructures by Application of Electro-Modulation Techniques

Papadimitriou

2019

Applied Sciences

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“…( ) [21] ( ) ( ) [22] where Pt m γ and V γ are the sensitivity functions of Pt m and V . Since the sensitivity function of Pt m is equal to 1 (in virtue of equations [3] and [5]), equations [20] and [22]…”

Section: Numerical Algorithm To Solve Problemmentioning

confidence: 99%

Mathematical Optimization of the Spatial Distribution of Platinum Particles in the Catalyst Layer of PEMFCs

Lamb

Mixon²,

Andrei

2017

ECS Trans.

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An adjoint-space technique is presented for the large-scale optimization (i.e. optimization with over 10 2 design variables) of the catalyst distribution in fuel cells. The algorithm is based on evaluating the catalyst sensitivity functions of the discharge voltage under specified current conditions. The catalyst sensitivity functions are computed efficiently using a gradient maximization algorithm, which requires solving a small number of sparse linear systems of equations to find the Gâtaux derivatives of the discharge current of the cell with respect to the design variables. It is shown that the optimum distribution of the catalyst varies with the discharge conditions, with the positions of landings and openings, as well as with the geometry and dimensions of the layers. It should be noted that our numerical algorithm can be used to describe the complete profile of the optimal catalyst by providing the full (mathematically exact) distribution of platinum particles in the catalyst layer.

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“…Most of the existing work related to the analysis of RDF effects in semiconductor devices focuses on the study of the variability of threshold voltages [10], current characteristics [11], and small-signal parameters [12] in field-effecttransistors and there are practically no studies related to the variability of C-V curves besides a few recent conference presentations [6,13,14]. Next, we present a number of simulation studies that show the substantial effect that the discrete nature of dopant impurities has on the lowfrequency differential capacitance in SCM measurements.…”

Section: Rdf Effects On the C-v Characteristicsmentioning

confidence: 99%

“…2(d). Although the depletion layer extends for a few tens of nm in the bulk of the semiconductor, the total number of dopants in this layer is relatively small (usually less than 10) and depends on the bias voltage [13]. The simulated differential capacitance is presented in Figs.…”

Section: Rdf Effects On the C-v Characteristicsmentioning

confidence: 99%

“…The numerical algorithm that we present below can be applied to any transport model that can be used to simulate the C-V curves, such as the classical drift-diffusion model, the semiclassical Boltzmann equation, or the quantum NEGF method. We assume that the doping sensitivity functions of the differential capacitance can be computed by using the numerical techniques presented in references [13,20].…”

Section: Numerical Algorithmmentioning

confidence: 99%

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Untitled

2016

Adv. Electr. Comp. Eng.

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In this article we investigate the possibility to use scanning capacitance microscopy (SCM) for the 2-D and 3-D "atomistic" dopant profiling of semiconductor materials. For this purpose, we first analyze the effects of random dopant fluctuations (RDF) on SCM measurements with nanoscale probes and show that the discrete and random locations of dopant impurities significantly affect the differential capacitance measured in SCM experiments if the dimension of the probe is below 50 nm. Then, we present an algorithm to compute the x, y, and z coordinates of the ionized impurities in the semiconductor material using a set of SCM measurements. The algorithm is based on evaluating the doping sensitivity functions of the differential capacitance and uses a gradientbased iterative method to compute the locations of dopants. Finally, we discuss a standard simulation case and show that we are able to successfully retrieve the locations of the ionized impurities using the proposed algorithm.

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Challenges and opportunities in atomistic dopant profiling using capacitance-voltage measurements

Cited by 7 publications

References 9 publications

Calibration of Polarization Fields and Electro-Optical Response of Group-III Nitride Based c-Plane Quantum-Well Heterostructures by Application of Electro-Modulation Techniques

Calibration of Polarization Fields and Electro-Optical Response of Group-III Nitride Based c-Plane Quantum-Well Heterostructures by Application of Electro-Modulation Techniques

Mathematical Optimization of the Spatial Distribution of Platinum Particles in the Catalyst Layer of PEMFCs

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