ETCH Rate and Thickness Measurements of Layered GaAs, AlAs and AlGaAs Structures Using a Laser Reflectance Technique

1994 ◽  
Vol 340 ◽  
Author(s):  
Louise H. Grober ◽  
M. Hong ◽  
R.D. Grober ◽  
J.P. Mannaerts ◽  
R.S. Freund
Keyword(s):  
Computer Simulation ◽  
Theoretical Model ◽  
Etch Rate ◽  
Etch Depth ◽  
Laser Reflectance ◽  
Layer Structures ◽  
Etch Rates ◽  
Thickness Measurements ◽  
Laser Reflectometry

ABSTRACTLaser reflectometry has been shown to be a useful tool for etch depth measurements during etching of multiple layer structures. We have extended the use of laser reflectometry to accurately determine the etch rates of GaAs, Al0.4Ga0.6As and AlAs as a function of temperature and to verify layer thickness in-situ. By use of computer simulation we compare a theoretical model to actual data to determine layer thicknesses and accurate etch rates. We compare our data to previously published work for GaAs etching.

Laser Reflectance Interferometry for In Situ Determination of Silicon Etch Rate in Various Solution

1999 ◽  
Vol 146 (10) ◽  
pp. 3890-3895 ◽  
Author(s):  
Elin Steinsland ◽  
Terje Finstad ◽  
Anders Hanneborg
Keyword(s):  
Etch Rate ◽  
Laser Reflectance

In Situ Control of Wet Etching Using Spectroscopic Ellipsometry

1998 ◽  
Vol 535 ◽  
Author(s):  
Sang-Jun Cho ◽  
P. G. Snyder
Keyword(s):  
Citric Acid ◽  
Real Time ◽  
Spectroscopic Ellipsometry ◽  
Wet Etching ◽  
Etch Depth ◽  
Algaas Layer ◽  
In Situ Control ◽  
Etch Rates

AbstractEtching of a GaAs/Al0.3Ga0.7As/GaAs heterostructure in a nonselective etch solution of 25:1:75 (citric acid: H2O2:H2O) was studied in-situ using real time spectroscopic ellipsometry (RTSE). Etch rates for GaAs and AIGaAs of 15.3 nm/min and 17.6 nm/min, respectively, were determined by numerically fitting RTSE data. RTSE was successfully used to stop the etch after removal of the thin GaAs cap, while removing very little of the underlying AlGaAs layer. In addition, etch depth into the AIGaAs layer was accurately controlled, using RTSE to stop the etch with 100 nm remaining. Finally, RTSE data for wet etching of a patterned sample (75% coverage with photoresist) showed similar behavior to that for the unpattemed sample.

scholarly journals Measuring and inferring the ice thickness distribution of four glaciers in the Tien Shan, Kyrgyzstan

2020 ◽  
pp. 1-18
Author(s):  
Lander Van Tricht ◽  
Philippe Huybrechts ◽  
Jonas Van Breedam ◽  
Johannes J. Fürst ◽  
Oleg Rybak ◽  
...  
Keyword(s):  
Cross Validation ◽  
Thickness Distribution ◽  
Tien Shan ◽  
Ice Thickness ◽  
Ice Volume ◽  
In Situ Data ◽  
Radio Echo Sounding ◽  
Thickness Measurements ◽  
Tien Shan Mountains

Abstract Glaciers in the Tien Shan mountains contribute considerably to the fresh water used for irrigation, households and energy supply in the dry lowland areas of Kyrgyzstan and its neighbouring countries. To date, reconstructions of the current ice volume and ice thickness distribution remain scarce, and accurate data are largely lacking at the local scale. Here, we present a detailed ice thickness distribution of Ashu-Tor, Bordu, Golubin and Kara-Batkak glaciers derived from radio-echo sounding measurements and modelling. All the ice thickness measurements are used to calibrate three individual models to estimate the ice thickness in inaccessible areas. A cross-validation between modelled and measured ice thickness for a subset of the data is performed to attribute a weight to every model and to assemble a final composite ice thickness distribution for every glacier. Results reveal the thickest ice on Ashu-Tor glacier with values up to 201 ± 12 m. The ice thickness measurements and distributions are also compared with estimates composed without the use of in situ data. These estimates approach the total ice volume well, but local ice thicknesses vary substantially.

The Formation of an Epitaxial-Graphene Cap Layer for Post-Implantation High Temperature Annealing of SiC and its In Situ Removal by Si-Vapor Etching

2011 ◽  
Vol 679-680 ◽  
pp. 777-780 ◽  
Author(s):  
Shoji Ushio ◽  
Ayumu Adachi ◽  
Kazuhiro Matsuda ◽  
Noboru Ohtani ◽  
Tadaaki Kaneko
Keyword(s):  
High Temperature ◽  
Graphene Layer ◽  
Treatment Method ◽  
Etch Depth ◽  
High Temperature Annealing ◽  
Large Area ◽  
Vapor Flux ◽  
Precise Control ◽  
Post Implantation

As a new graphene functionality applicable to post-implantation high temperature annealing of SiC, a method of in situ formation and removal of large area epitaxial few-layer graphene on 4H-SiC(0001) Si-face is proposed. It is demonstrated that the homogeneous graphene layer formed by Si sublimation can be preserved without the decomposition of the underlying SiC substrate even in the excess of 2000 oC in ultrahigh vacuum. It is due to the existence of the stable (6√3×6√3) buffer layer at the interface. To ensure this cap function, the homogeneity of the interface must be guaranteed. In order to do that, precise control of the initial SiC surface flatness is required. Si-vapor etching is a simple and versatile SiC surface pre/post- treatment method, where thermally decomposed SiC surface is compensated by a Si-vapor flux from Si solid source in the same semi-closed TaC container. While this Si-vapor etching allows precise control of SiC etch depth and surface step-terrace structures, it also provides a “decap” function to remove of the graphene layer. The surface properties after the each process were characterized by AFM and Raman spectroscopy.

scholarly journals Влияние электромиграции на зарождение вакансионных островков на поверхности Si(100) при сублимации

2019 ◽  
Vol 53 (6) ◽  
pp. 805
Author(s):  
С.В. Ситников ◽  
Е.Е. Родякина ◽  
А.В. Латышев
Keyword(s):  
Electron Microscopy ◽  
Theoretical Model ◽  
Temperature Dependence ◽  
Effective Charge ◽  
Positive Sign ◽  
Nucleation Center ◽  
Island Nucleation ◽  
Reflection Electron Microscopy ◽  
Elementary Charge

AbstractBy means of in situ ultrahigh vacuum reflection electron microscopy, the nucleation of vacancy islands on wide terraces of the Si(100) surface is investigated. The temperature dependence of the displacement of a vacancy island nucleation center is determined in the process of heating a sample with a dc electric current. On the basis of a theoretical model, the effective electric charge of addimers is estimated in the direction across dimer rows of the surface. The effective charge has a positive sign and does not exceed 15 units of the elementary charge in the temperature range of 1020–1120°C.

In Situ Auger Spectroscopy Investigation of InP Surfaces Treated in RF Hydrogen and Hydrogen/Methane/Argon Plasmas

1995 ◽  
Vol 386 ◽  
Author(s):  
J. E. Parmeter ◽  
R. J. Shul ◽  
P. A. Miller
Keyword(s):  
Hydrogen Plasma ◽  
Auger Spectroscopy ◽  
Surface Roughening ◽  
Rf Power ◽  
Plasma Exposure ◽  
Argon Plasmas ◽  
Etch Rates ◽  
Phosphorus Depletion ◽  
Oxygen Impurities

ABSTRACTWe have used in situ Auger spectroscopic analysis to investigate the composition of InP surfaces cleaned in rf H2 plasmas and etched in rf H2/CH4/Ar plasmas. In general agreement with previous results, hydrogen plasma treatment is found to remove surface carbon and oxygen impurities but also leads to substantial surface phosphorus depletion if not carefully controlled. Low plasma exposure times and rf power settings minimize both phosphorus depletion and surface roughening. Surfaces etched in H2/CH4/Ar plasmas can show severe phosphorus depletion in high density plasmas leading to etch rates of ∼ 700 Å/min, but this effect is greatly reduced in lower density plasmas that produce etch rates of 30–400 Å/min.

A Mechanism of Sliding on the Nanometer-Thick Ag Layers

2005 ◽  
Author(s):  
F. Honda ◽  
M. Goto
Keyword(s):  
Friction Coefficient ◽  
Normal Load ◽  
High Vacuum ◽  
High Energy ◽  
Thin Layers ◽  
Ultra High Vacuum ◽  
Wear And Friction ◽  
Thickness Measurements

Tribological performance of sub-nano to nanometer-thick Ag layers deposited on Si(111) have been examined to understand the role of surface thin layers to the wear and friction characteristics. The slider was made of diamond sphere of 3 mm in radius. Sliding tests were carried out in an ultra-high vacuum environment (lower than 4 × 10−8 Pa) and analyzed in-situ by Auger electron spectroscopy (AES) for the quantitative thickness-measurements, by reflection high-energy electron diffraction (RHEED) to clarify the substrate cleanliness and crystallography of the Ag films, and by scanning probe microscopy (SPM) for the morphology of the deposited/slid film surfaces. As the results, a minimum of the friction coefficient 0.007 was observed from the film thickness range of 1.5–10 nm, and exactly no worn particles were found after 100 cycles of reciprocal sliding. Results have directly indicated that solid Ag(111) sliding planes allowed to reduce the friction coefficient very low without any detectable wear particles, and Ag nanocrystallites in Ag polycrystalline layers increase the size to 20–40 nm order, during sliding. The friction coefficient was slightly dependent to the normal load. Results were discussed on the role of the surface atoms to the friction, and a mechanism of sliding on Ag thin layers.

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