Studies of Oxide Desorption From GaAs by Diffuse Electron Scatfering and Optical Reflectivity

1991 ◽  
Vol 222 ◽  
Author(s):  
T. Van Buuren ◽  
T. Tiedje ◽  
M. K. Weilmeier ◽  
K. M. Colbow ◽  
J. A. Mackenzie
Keyword(s):  
Oxygen Plasma ◽  
Oxide Thickness ◽  
High Energy ◽  
Secondary Electrons ◽  
Oxide Layers ◽  
Gaas Substrates ◽  
Pressure Oxygen ◽  
High Energy Electrons ◽  
Order Of Magnitude ◽  
Magnitude Increase

ABSTRACTWe have determined that the temperature for desorption of gallium oude from GaAs increases linearly with oxide thickness, for oxide layers between about 6Å and 26Å thick. Different thicknesses of oxide layers were created by varying the exposure time of the GaAs wafers to a low pressure oxygen plasma. In addition, we show by diffuse light scattering that highly polished GaAs substrates roughen during the oxide desorption. These results are interpreted in terms of a model in which the oxide evaporates inhomogeneously. The oxide desorption was also studied by monitoring the secondary electrons produced by the high energy electrons from the RHEED gun. After the gallium oxide desorption there is a reversible, order of magnitude, increase in the number of secondary electrons produced. We interpret this result as evidence for the formation of microscopic gallium droplets on the GaAs surface.

Migrations of Interstitial Atoms in Semiconductors (Surface Diffusion and Kick-Out Mechanism)

1989 ◽  
Vol 163 ◽  
Author(s):  
Takao Wada ◽  
Akihiro Takeda ◽  
Masaya Ichimura ◽  
Michihiko Takeda
Keyword(s):  
Electron Beam ◽  
Surface Diffusion ◽  
High Energy ◽  
Gaas Substrates ◽  
High Energy Electrons ◽  
Interstitial Atoms

AbstractGe and Zn atoms were introduced into the unirradiated regions of Si at 150°C and GaAs wafers at 50°C, respectively by using the electron-beam doping method. The surfaces of Si and GaAs substrates were covered partially by the overlayers of Ge and Zn sheets, respectively. The only surfaces of the Ge and Zn sheets were irradiated locally. with high energy electrons at 7MeV with the fluences of 5×1017 – 1×1018 electrons cm-2 . Even at a distance of ~10mm from the irradiated overlayers in the Si and GaAs substrates, Ge and Zn atoms respectively, whose interstitials may migrate the unirradiated regions, were detected by SIMS measurements. PL signal due to band-to-acceptor (ZnGa ) transition at 1.48eV becomes observable after annealing at 800°C for 20mm in the unirradiated GaAs region, which is separated from Zn sheet by nearly 10mm.

Emission of secondary electrons from various targets under the action of high-energy electrons

1977 ◽  
Vol 43 (2) ◽  
pp. 743-746 ◽  
Author(s):  
G. Ya. Chernov ◽  
A. F. Akkerman ◽  
V. A. Botvin
Keyword(s):  
High Energy ◽  
Secondary Electrons ◽  
High Energy Electrons

SiO2/Si Interfaces Studied by Stm and Hrtem

1990 ◽  
Vol 183 ◽  
Author(s):  
Masaaki Niwa ◽  
Minoru Onoda ◽  
Hiroshi Iwasaki ◽  
Robert Sinclair
Keyword(s):  
Oxide Thickness ◽  
High Energy ◽  
Interface Roughness ◽  
Oxide Interface ◽  
Oxide Interfaces ◽  
Polysilicon Gate ◽  
High Energy Electrons ◽  
Stm Image ◽  
Mos Structures ◽  
Good Agreement

AbstractThe morphology of SiO2/Si interfaces in a semiconductor LOCOS active area grown by several oxidation conditions has been studied, to compare the roughness of the interfaces observed by STM and HRTEM in particular. Samples consisted of typical MOS structures with a polysilicon gate/SiO2/Si(100). Hydrogen terminated Si surfaces were prepared by means of HF dipping for STM observations. The interface roughness of a “dry” oxide observed by HRTEM was slightly larger than that of a “wet” oxide. Good agreement could be found between STM and HRTEM for the wet oxide interfaces. As for the dry oxide interface, it was more difficult to obtain a reproducible STM image than for the wet oxide interface, but the reverse was true for HRTEM. During the HRTEM, high energy electrons damage the sample and reduce the oxide thickness, especially in the wet oxide samples.

Electroluminescence Device Perspectives of Si+-Implanted SiO2

1996 ◽  
Vol 452 ◽  
Author(s):  
F. Kozlowski ◽  
H. E. Porteanu ◽  
V. Petrova-Koch ◽  
F. Koch
Keyword(s):  
Electrical Current ◽  
High Energy ◽  
Porous Si ◽  
Oxide Layers ◽  
Electroluminescent Device ◽  
High Energy Electrons ◽  
Thermal Oxide ◽  
Electroluminescence Device

AbstractThermal oxide layers on Si which have been implanted with Si conduct electrical current and emit light. The electroluminescence effect (EL) has an efficiency which is comparable to the best values that have been reported for the porous Si based devices. Generally, the EL spectrum differs substantially from the photoexcited luminescence. It is linked with that excited by external high energy electrons in cathodoluminescence (CL) experiments. We suggest to consider the effect as internal CL. Based on studies of transport and EL characteristic we evaluate the possibilities of an electroluminescent device based on such layers.

Magnetic microstructure imaging by secondary electron spin polarization analysis

1986 ◽  
Vol 44 ◽  
pp. 634-635
Author(s):  
G. G. Hembree ◽  
J. Unguris ◽  
R. J. Celotta ◽  
D. T. Pierce
Keyword(s):  
Spin Polarization ◽  
Secondary Electron ◽  
Ferromagnetic Material ◽  
High Energy ◽  
Electron Spin Polarization ◽  
Magnetic Domains ◽  
Secondary Electrons ◽  
Magnetic Microstructure ◽  
High Energy Electrons ◽  
Hemispherical Energy Analyzer

Recent research has shown that the low energy secondary electrons generated from ferromagnetic material are spin polarized. The secondary electron polarization yields a signal which is directly proportional to the magnitude and direction of the magnetization within the volume of material in which the electrons were generated. This signal can be used in a scanning electron microscope to image the microstructure of magnetic domains on the surface of ferromagnetic materials.We have incorporated a new compact spin polarization analyzer into a commercial UHV SEM. A schematic diagram of the apparatus is shown in Fig. 1. The secondary electrons are extracted from the sample and are then focused into a hemispherical energy analyzer which filters out the high energy electrons.

Optimisation of the S.E. Signal to Background Ratio in ESEM

1998 ◽  
Vol 4 (S2) ◽  
pp. 296-297
Author(s):  
T.H. Keller ◽  
B.L. Thiel ◽  
A.M. Donald
Keyword(s):  
Experimental Study ◽  
Secondary Electron ◽  
High Energy ◽  
Background Signal ◽  
Secondary Electrons ◽  
Background Ratio ◽  
Backscattered Electrons ◽  
High Energy Electrons ◽  
Gas Molecules ◽  
Environmental Sem

We have performed a theoretical and experimental study of the signal composition in the Environmental SEM (ESEM) with the intention of forming a set of general guidelines for optimising the signal to background ratio. In the ElectroScan ESEM, a gas ionisation cascade is used to amplify the secondary electron signals emanating from the specimen surface. The presence of gas in the chamber also gives rise to a pressure dependent background signal derived from ionisation events between gas molecules and high energy primary beam and backscattered electrons, as well as secondary electrons generated by the probe skirt.The signal collected by an environmental secondary detector (ESD) (ElectroScan, 1991) or a gaseous secondary detector (GSED) (ElectroScan, 1994) is an amplified signal which is a composite of at least three contributions. These are the amplified currents arising from the ionisation of the gas by high energy electrons from the primary (Ipe) and backscattered electrons (Ihse).

Mechanical Interaction in Near-Field Spectroscopy of single Semiconductor Quantum Dots.

2002 ◽  
Vol 722 ◽  
Author(s):  
A. M. Mintairov ◽  
P. A. Blagnov ◽  
O. V. Kovalenkov ◽  
C. Li ◽  
J. L. Merz ◽  
...  
Keyword(s):  
Near Field ◽  
Local Strain ◽  
High Energy ◽  
Emission Lines ◽  
Mechanical Interaction ◽  
Aperture Diameter ◽  
Self Organized ◽  
Order Of Magnitude ◽  
Single Quantum Dot ◽  
Magnitude Increase

AbstractWe have studied high-energy shifts of single quantum dot (QD) emission lines induced by contact pressure exerted by a near-field optical fiber tip. “Pressure” coefficients of 0.65-3 meV/nm have been measured for self-organized InAs/GaAs, InAs/AlAs and InP/GaInP QDs in agreement with numerical calculations of the local strain field. We found an increase of the tipinduced pressure with increasing aperture diameter from 50-300 nm. A correlation between the shift rate and QD stiffness was obtained. We also observed an order of magnitude increase of single QD emission intensity with increased pressure.

scholarly journals Радиационная стойкость гетеропереходных солнечных элементов alpha-Si : H/Si с тонким внутренним слоем i-alpha-Si : H

2018 ◽  
Vol 44 (17) ◽  
pp. 95
Author(s):  
В.С. Калиновский ◽  
Е.И. Теруков ◽  
Е.В. Контрош ◽  
В.Н. Вербицкий ◽  
A.С. Титов
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
High Energy ◽  
Heterojunction Solar Cell ◽  
Silicon Solar Cells ◽  
Photoelectric Characteristics ◽  
High Energy Electrons ◽  
Order Of Magnitude

AbstractWe have studied the degradation of photoelectric characteristics of heterojunction solar cell samples based on α-Si:H/Si structures upon irradiation by electrons with an energy of 3.8 MeV and fluences of 1 × 10^12–1 × 10^14 cm^–2. It is shown that the efficiency of the samples of heterojunction solar cell elements under the conditions of AM0 illumination (0.136 W/cm^2) is reduced by 25% at a fluence of 2 × 10^13 cm^–2. This is more than an order of magnitude higher than the critical fluence value achieved previously when silicon solar cells with a p–n junction and an n -type base were irradiated by high-energy electrons.

Analysis of Voltage Contrast in Secondary Electron Images Using a High-Energy Electron Spectrometer

2019 ◽  
Author(s):  
Natsuko Asano ◽  
Shunsuke Asahina ◽  
Natasha Erdman
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Sample Surface ◽  
High Energy ◽  
Secondary Electrons ◽  
Analysis Technique ◽  
Quantitative Understanding ◽  
Voltage Contrast ◽  
Acceleration Voltage ◽  
Failure Localization

Abstract Voltage contrast (VC) observation using a scanning electron microscope (SEM) or a focused ion beam (FIB) is a common failure analysis technique for semiconductor devices.[1] The VC information allows understanding of failure localization issues. In general, VC images are acquired using secondary electrons (SEs) from a sample surface at an acceleration voltage of 0.8–2.0 kV in SEM. In this study, we aimed to find an optimized electron energy range for VC acquisition using Auger electron spectroscopy (AES) for quantitative understanding.

Sign in / Sign up

Export Citation Format

Share Document