Contactless measurement of sheet resistance and mobility of inversion charge carriers on photovoltaic wafers

Conductive nanomaterials are widely studied and used. The four-point probe method has been widely used to measure nanomaterials’ sheet resistance, denoted as Rs. However, for materials sensitive to contamination or physical damage, contactless measurement is highly recommended if not required. Feasibility of Rs evaluation using a one-port rectangular waveguide working on the microwave band in a contact-free mode is studied. Compared with existed waveguide methods, the proposed method has three advantages: first, by introducing an air gap between the waveguide flange and the sample surface, it is truly contactless; second, within the specified range of Rs, the substrate’s effect may be neglected; third, it does not require a matched load and/or metallization at the sample backside. Both theoretical derivation and simulation showed that the magnitude of the reflection coefficient S11 decreased monotonously with increasing Rs. Through calibration, a quantitative correlation of S11 and Rs was established. Experimental results with various conductive glasses showed that, for Rs in the range of ~10 to 400 Ohm/sq, the estimation error of sheet resistance was below ~20%. The potential effects of air gap size, sample size/location and measurement uncertainty of S11 are discussed. The proposed method is particularly suitable for characterization of conductive glass or related nanomaterials with Rs in the range of tens or hundreds of Ohm/sq.

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Contactless mobility measurements of inversion charge carriers on silicon substrates with SiO2 and HfO2 gate dielectrics

Applied Physics Letters ◽

10.1063/1.3373920 ◽

2010 ◽

Vol 96 (12) ◽

pp. 122906 ◽

Cited By ~ 6

Author(s):

J. L. Everaert ◽

E. Rosseel ◽

J. Dekoster ◽

A. Pap ◽

A. Meszaros ◽

...

Keyword(s):

Gate Dielectrics ◽

Charge Carriers ◽

Silicon Substrates ◽

Inversion Charge

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Detector strategies for environmental scanning electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100131115 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1296-1297

Author(s):

Klaus-Ruediger Peters

Keyword(s):

High Vacuum ◽

Environmental Scanning Electron Microscopy ◽

Charge Carriers ◽

Environmental Scanning ◽

Surface Information ◽

X Ray ◽

Detector Electrode ◽

Electrons And Ions ◽

Low Energy Electrons ◽

Environmental Sem

Environmental SEM operate at specimen chamber pressures of ∼20 torr (2.7 kPa) allowing stabilization of liquid water at room temperature, working on rugged insulators, and generation of an environmental secondary electron (ESE) signal. All signals available in conventional high vacuum instruments are also utilized in the environmental SEM, including BSE, SE, absorbed current, CL, and X-ray. In addition, the ESEM allows utilization of the flux of charge carriers as information, providing exciting new signal modes not available to BSE imaging or to conventional high vacuum SEM.In the ESEM, at low vacuum, SE electrons are collected with a “gaseous detector”. This detector collects low energy electrons (and ions) with biased wires or plates similar to those used in early high vacuum SEM for SE detection. The detector electrode can be integrated into the first PLA or positioned at any other place resulting in a versatile system that provides a variety of surface information.

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Direct imaging of charge transfer

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100165860 ◽

1996 ◽

Vol 54 ◽

pp. 680-681

Author(s):

Yimei Zhu ◽

J. Tafto

Keyword(s):

Charge Transfer ◽

Electron Diffraction ◽

Scattering Amplitude ◽

High Temperature Superconductors ◽

Charge Carriers ◽

Image Charge ◽

Net Charge ◽

Long Time ◽

Electron Holes ◽

First Time

The electron holes confined to the CuO2-plane are the charge carriers in high-temperature superconductors, and thus, the distribution of charge plays a key role in determining their superconducting properties. While it has been known for a long time that in principle, electron diffraction at low angles is very sensitive to charge transfer, we, for the first time, show that under a proper TEM imaging condition, it is possible to directly image charge in crystals with a large unit cell. We apply this new way of studying charge distribution to the technologically important Bi2Sr2Ca1Cu2O8+δ superconductors.Charged particles interact with the electrostatic potential, and thus, for small scattering angles, the incident particle sees a nuclei that is screened by the electron cloud. Hence, the scattering amplitude mainly is determined by the net charge of the ion. Comparing with the high Z neutral Bi atom, we note that the scattering amplitude of the hole or an electron is larger at small scattering angles. This is in stark contrast to the displacements which contribute negligibly to the electron diffraction pattern at small angles because of the short g-vectors.

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The outlook for the development of radiation sources in the middle-IR range based on the intraband transitions between the energy levels of charge carriers in injection laser heterostructures with quantum dots and wells

Uspekhi Fizicheskih Nauk ◽

10.3367/ufnr.0169.199904g.0459 ◽

1999 ◽

Vol 169 (4) ◽

pp. 459 ◽

Cited By ~ 1

Author(s):

L.E. Vorob'ev ◽

D.A. Firsov ◽

V.A. Shalygin ◽

V.N. Tulupenko ◽

N.N. Ledentsov ◽

...

Keyword(s):

Quantum Dots ◽

Energy Levels ◽

Injection Laser ◽

Charge Carriers ◽

Laser Heterostructures ◽

Radiation Sources

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CONTACTLESS MEASUREMENT OF ELECTROMAGNETIC PARAMETERS OF NANOMATERIALS

Автометрия ◽

10.15372/aut20160412 ◽

2016 ◽

Keyword(s):

Contactless Measurement ◽

Electromagnetic Parameters

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Effect of a Ti-capped and Ti-mediated Layer on Co Silicide Formation

MRS Proceedings ◽

10.1557/proc-716-b10.5 ◽

2002 ◽

Vol 716 ◽

Author(s):

G.Z. Pan ◽

E.W. Chang ◽

Y. Rahmat-Samii

Keyword(s):

Electron Diffraction ◽

Sheet Resistance ◽

Thermal Annealing ◽

Rapid Thermal Annealing ◽

Diffusion Barrier ◽

Silicide Formation ◽

Plan View ◽

Processing Window

AbstractWe comparatively studied the formation of ultra thin Co silicides, Co2Si, CoSi and CoSi2, with/without a Ti-capped and Ti-mediated layer by using rapid thermal annealing in a N2 ambient. Four-point-probe sheet resistance measurements and plan-view electron diffraction were used to characterize the silicides as well as the epitaxial characteristics of CoSi2 with Si. We found that the formation of the Co silicides and their existing duration are strongly influenced by the presence of a Ti-capped and Ti-mediated layer. A Ti-capped layer promotes significantly CoSi formation but suppresses Co2Si, and delays CoSi2, which advantageously increases the silicidation-processing window. A Ti-mediated layer acting as a diffusion barrier to the supply of Co suppresses the formation of both Co2Si and CoSi but energetically favors directly forming CoSi2. Plan-view electron diffraction studies indicated that both a Ti-capped and Ti-mediated layer could be used to form ultra thin epitaxial CoSi2 silicide.

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Laser Engineering of Barrier Structures Based on Solid Solution ZnCdHgTe.

MRS Proceedings ◽

10.1557/proc-719-f8.35 ◽

2002 ◽

Vol 719 ◽

Author(s):

Galina Khlyap

Keyword(s):

Room Temperature ◽

Film Surface ◽

Charge Carriers ◽

Barrier Structure ◽

Free Charge ◽

Current Voltage ◽

Capacitance Voltage ◽

Laser Engineering ◽

Charged Defects ◽

Epilayer Surface

AbstractRoom-temperature electric investigations carried out in CO2-laser irradiated ZnCdHgTe epifilms revealed current-voltage and capacitance-voltage dependencies typical for the metal-semiconductor barrier structure. The epilayer surface studies had demonstrated that the cell-like relief has replaced the initial tessellated structure observed on the as-grown samples. The detailed numerical analysis of the experimental measurements and morphological investigations of the film surface showed that the boundaries of the cells formed under the laser irradiation are appeared as the regions of accumulation of derived charged defects of different type of conductivity supplying free charge carriers under the applied electric field.

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