Effect of Electron-Electron Scattering on the Carrier Distribution in Semiconductor Devices

2018 ◽  
Author(s):  
Hans Kosina ◽  
Markus Kampl
Keyword(s):  
Electron Scattering ◽  
Semiconductor Devices ◽  
Carrier Distribution

Diagnostics of semiconductor structures by electrochemical capacitance-voltage profiling technique

2021 ◽  
Vol 87 (1) ◽  
pp. 35-44
Author(s):  
G. E. Yakovlev ◽  
D. S. Frolov ◽  
V. I. Zubkov
Keyword(s):  
Quantum Wells ◽  
Concentration Distribution ◽  
Semiconductor Devices ◽  
Multiple Quantum ◽  
Carrier Distribution ◽  
Electrochemical Capacitance ◽  
Informative Feedback ◽  
Semiconductor Structures ◽  
Capacitance Voltage ◽  
Gan Heterostructure

The properties of interfaces in the heterostructures which frequently govern their operation are of particular importance for the devices containing heterostructures as active elements. Any further improving of the characteristics of semiconductor devices is impossible without a detail analysis of the processes occurring at the interfaces of heterojunctions. At the same time, the results largely depend on the purity of the starting materials and the technology of layer manufacturing. Moreover, the requirements to the composition and distribution of the impurity steadily get stringent. Therefore, the requirements regarding the methods of the impurity control and carrier distribution also become tougher both in the stage of laboratory development of the structure and in various stages of manufacturing of semiconductor devices. Electrochemical capacitance-voltage profiling is distinguished among the methods of electrical diagnostics of semiconductors by the absence of special preparation of the structures and deposition of the contacts to perform measurements, thus providing for gaining information not only about the impurity distribution but also about the distribution of free carriers. The goal of this work is to perform precise measurements of the profiles of free carrier distribution in semiconductor structures of different types, and demonstrate the measuring capabilities of a modern technique for concentration distribution diagnostics, i.e., electrochemical capacitance-voltage profiling. The method allows verification of the layer thickness in semiconductor heterostructures and provide a useful and informative feedback to technologists. To increase the resolution of the method and broad up the range of available test frequencies, a standard electrochemical profiler has been modified. Mapping data for GaAs substrate structure, the profiles of the concentration distribution of the majority charge carriers in SiC structures, GaAs structure with a p – n junction, pHEMT heterostructure, GaN heterostructure with multiple quantum wells, and in a silicon-based solar cell heterostructure are presented. The obtained results can be used to analyze the physical properties and phenomena in semiconductor devices with quantum-sized layers, as well as to improve and refine the parameters of existing electronic devices.

Evaluation of Power SiC-MOSFET Using Super-Higher-Order Scanning Nonlinear Dielectric Microscopy—Imaging of Carrier Distribution and Depletion Layer

2014 ◽  
Author(s):  
N. Chinone ◽  
Y. Cho ◽  
T. Nakamura
Keyword(s):  
Semiconductor Device ◽  
Low Cost ◽  
Semiconductor Devices ◽  
Higher Order ◽  
Depletion Layer ◽  
Dopant Distribution ◽  
Carrier Distribution ◽  
Microscopy Imaging ◽  
Nonlinear Dielectric ◽  
Power Semiconductor

Abstract Evaluation techniques for semiconductor devices are keys for device development with low cost and short time to market. Especially, dopant and depletion layer distribution in devices is a critical electrical property that needs to be evaluated. Super-higher-order nonlinear dielectric microscopy (SHOSNDM) is one of the promising techniques for semiconductor device evaluation. We developed a method for imaging detailed dopant distribution and depletion layers in semiconductor devices using SHO-SNDM. As a demonstration, a cross-section of a SiC power semiconductor device was measured by this method and detailed dopant distribution and depletion layer distributions were imaged.

scholarly journals THE INTENSITY OF SCATTERING OF CHARGE CARRIERS IN GRAPHENE, LOCATED ON A SUBSTRATE OF HEXAGONAL BORON NITRIDE

Doklady BGUIR ◽  
2019 ◽  
pp. 141-148
Author(s):  
V. V. Muraviev ◽  
V. N. Mishchenko
Keyword(s):  
Boron Nitride ◽  
Electron Energy ◽  
Electron Scattering ◽  
Hexagonal Boron Nitride ◽  
Semiconductor Devices ◽  
Single Layer ◽  
Charge Carriers ◽  
Optical Phonons ◽  
Fixed Rate ◽  
Graphene Electron

The results of modeling the scattering intensities of charge carriers in graphene located on a substrate of hexagonal boron nitride are presented. Graphene is considered a promising material for the formation of new semiconductor devices with good characteristics for the microwave and HF bands. Formulas are presented that allow modeling of the main electron scattering intensities in a single layer of graphene placed on a substrate of boron nitride. The dependences of the scattering intensity on optical phonons associated with the interface between graphene and a layer of hexagonal boron nitride are obtained when the thickness of the gap between these layers changes. Simulation of fixed rate dispersion was carried out as for normal temperature equal to 300 K and at elevated – equal to 370, which is connected with the necessity of considering the temperature rise of the graphene layer with increasing electron energy. The analysis of the obtained dependences showed that at electron energy values that exceed a value equal to approximately 0.165 eV, there is a predominance of electron scattering on optical phonons inherent in the inner layer of graphene, electron-electron scattering, as well as scattering on optical phonons associated with the interface between graphene and a layer of hexagonal boron nitride, over other types of scattering. At low energy values, which are less than about 0.03 eV, the dispersion on impurities prevails over other types of dispersion. Based on the obtained dependences of electron scattering intensities in graphene, it becomes possible to implement the Monte – Carlo statistical method to determine the characteristics of electron transfer in semiconductor devices containing layers of graphene and hexagonal boron.

Study of charge transfer in FeTi

1983 ◽  
Vol 41 ◽  
pp. 296-297
Author(s):  
J. Taft∅
Keyword(s):  
Charge Transfer ◽  
Charge Distribution ◽  
Electron Scattering ◽  
Periodic System ◽  
Electron Distribution ◽  
Scattering Amplitude ◽  
Transition Elements ◽  
Hartree Fock ◽  
Cscl Structure ◽  
The Right

It is well known that for reflections corresponding to large interplanar spacings (i.e., sin θ/λ small), the electron scattering amplitude, f, is sensitive to the ionicity and to the charge distribution around the atoms. We have used this in order to obtain information about the charge distribution in FeTi, which is a candidate for storage of hydrogen. Our goal is to study the changes in electron distribution in the presence of hydrogen, and also the ionicity of hydrogen in metals, but so far our study has been limited to pure FeTi. FeTi has the CsCl structure and thus Fe and Ti scatter with a phase difference of π into the 100-ref lections. Because Fe (Z = 26) is higher in the periodic system than Ti (Z = 22), an immediate “guess” would be that Fe has a larger scattering amplitude than Ti. However, relativistic Hartree-Fock calculations show that the opposite is the case for the 100-reflection. An explanation for this may be sought in the stronger localization of the d-electrons of the first row transition elements when moving to the right in the periodic table. The tabulated difference between fTi (100) and ffe (100) is small, however, and based on the values of the scattering amplitude for isolated atoms, the kinematical intensity of the 100-reflection is only 5.10-4 of the intensity of the 200-reflection.

Lithography below 100 nm

1983 ◽  
Vol 41 ◽  
pp. 96-99
Author(s):  
L. D. Jackel
Keyword(s):  
Spatial Distribution ◽  
Electron Beam ◽  
Electron Scattering ◽  
Electron Beam Lithography ◽  
Substrate Material ◽  
Local Electron ◽  
Electron Dose ◽  
Positive Resist ◽  
Exposure Process

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.

Artefact in 20Å-Resolution Electron Images of Negatively Stained Twodimensional Membrane Protein Crystals

1982 ◽  
Vol 40 ◽  
pp. 92-93
Author(s):  
Douglas L. Dorset ◽  
Barbara Moss
Keyword(s):  
Electron Scattering ◽  
Cross Correlation ◽  
Transmission Function ◽  
Group Symmetry ◽  
Asymmetric Structure ◽  
Object Model ◽  
Phase Object ◽  
Computing Systems ◽  
Resolution Electron ◽  
Plane Group

A number of computing systems devoted to the averaging of electron images of two-dimensional macromolecular crystalline arrays have facilitated the visualization of negatively-stained biological structures. Either by simulation of optical filtering techniques or, in more refined treatments, by cross-correlation averaging, an idealized representation of the repeating asymmetric structure unit is constructed, eliminating image distortions due to radiation damage, stain irregularities and, in the latter approach, imperfections and distortions in the unit cell repeat. In these analyses it is generally assumed that the electron scattering from the thin negativelystained object is well-approximated by a phase object model. Even when absorption effects are considered (i.e. “amplitude contrast“), the expansion of the transmission function, q(x,y)=exp (iσɸ (x,y)), does not exceed the first (kinematical) term. Furthermore, in reconstruction of electron images, kinematical phases are applied to diffraction amplitudes and obey the constraints of the plane group symmetry.

Chemical modification of the bacterial wall to determine sites of metal deposition

1978 ◽  
Vol 36 (2) ◽  
pp. 350-351
Author(s):  
T. J. Beveridge
Keyword(s):  
Electron Scattering ◽  
Metal Salt ◽  
Metal Deposition ◽  
Suitable Model ◽  
X Ray Diffraction ◽  
Subtilis Cell ◽  
Thin Sections ◽  
X Ray ◽  
Section Data ◽  
Metal Impregnation

The Bacillus subtilis cell wall provides a protective sacculus about the vital constituents of the bacterium and consists of a collection of anionic hetero- and homopolymers which are mainly polysaccharidic. We recently demonstrated that unfixed walls were able to trap and retain substantial amounts of metal when suspended in aqueous metal salt solutions. These walls were briefly mixed with low concentration metal solutions (5mM for 10 min at 22°C), were well washed with deionized distilled water, and the quantity of metal uptake (atomic absorption and X-ray fluorescence), the type of staining response (electron scattering profile of thin-sections), and the crystallinity of the deposition product (X-ray diffraction of embedded specimens) determined.Since most biological material possesses little electron scattering ability electron microscopists have been forced to depend on heavy metal impregnation of the specimen before obtaining thin-section data. Our experience with these walls suggested that they may provide a suitable model system with which to study the sites of reaction for this metal deposition.

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