Relationship Between Graded Layer Structures and Defects in Silicon-Germanium Virtual Substrates

2000 ◽  
Vol 648 ◽  
Author(s):  
Kazuki Mizushima ◽  
Ichiro Shiono ◽  
Kenji Yamaguchi ◽  
Naoki Muraki
Keyword(s):  
Surface Roughness ◽  
Silicon Germanium ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Vacuum System ◽  
Optimum Number ◽  
Threading Dislocation ◽  
Typical Sample ◽  
Dislocation Densities

AbstractSilicon-germanium virtual substrates have been synthesized by low-pressure chemical vapor deposition. We obtained threading dislocation densities ranging from 105 to 106 cm−2, surface roughness ranging from 1.5 to 4 nm, and also cross-hatch pattern densities, depending on the grading rate and top layer germanium composition. For the typical sample, which has a linear-graded structure with a grading rate of 20%/[µm, and germanium composition of 30 % at the top layer, we obtained dislocation densities of about 106 cm−2 and root mean squared surface roughness of about 3 nm. The obtained dislocation densities are equivalent with the virtual substrates synthesized by ultra-high vacuum system. On the other hand the surface roughness is superior to the typical reported values. In this study three kinds of structures, i.e. linear-graded, stepwise, and graded-step structures, were considered. We found the defects are effectively reduced by introduction of an optimum number of steps in the graded layer.

Progression of the Surface Roughness of N+ Silicon Epitaxial Films as Analyzed by AFM

1995 ◽  
Vol 399 ◽  
Author(s):  
S. John ◽  
E. J. Quinones ◽  
B. Ferguson ◽  
K. Pacheco ◽  
C. B. Mullins ◽  
...  
Keyword(s):  
Surface Roughness ◽  
High Vacuum ◽  
Film Surface ◽  
Chemical Vapor ◽  
Epitaxial Films ◽  
Ultra High Vacuum ◽  
Phosphorus Segregation ◽  
Surface Mobility ◽  
Partial Pressures ◽  
Effects Of Ph

ABSTRACTWe report on the morphology of heavily phosphorous doped silicon films grown by ultra high vacuum chemical vapor deposition at temperatures of ∼550° C. The effects of PH3 on epitaxial films have been examined for silicon deposited using SiH4 and Si2H6. It is found that films grown using silane experience an increase in surface roughness with increasing phosphine partial pressure. AFM and RHEED studies indicate 3-D growth. As epitaxy progresses, it is believed that phosphorus segregation on the growing film surface greatly diminishes the adsorption and surface mobility of the silicon bearing species. Initial Si deposition results in a pitted surface, but as growth advances and the phosphorus coverage increases, growth within the pits decreases the surface roughness. In contrast to SiH4, it is found that Si2H6 provides excellent quality, smooth films even at high PH3 partial pressures.

Nucleation and Growth of Polycrystalline Silicon Films in an Ultra high Vacuum Rapid Thermal Chemical Vapor Deposition Reactor Using Disilane and Hydrogen

1994 ◽  
Vol 343 ◽  
Author(s):  
Katherine E. Violette ◽  
Mehmet C. Öztürk ◽  
Gari Harris ◽  
Mahesh K. Sanganeria ◽  
Archie Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Surface Roughness ◽  
Chemical Vapor Deposition ◽  
Surface Morphology ◽  
Vapor Deposition ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Chemical Vapor Deposition Reactor ◽  
Thermal Chemical Vapor Deposition

A study of Si nucleation and deposition on SiO2 was performed using disilane and hydrogen in an ultra high vacuum rapid thermal chemical vapor deposition reactor in pressure and temperature ranges of 0.1 – 1.5 Torr and 625 – 750°C. The film analysis was carried out using scanning electron microscopy, transmission electron microscopy and atomic force microscopy. At lower pressures, an incubation time exists which leads to a retardation in film nucleation. At 750°C, the incubation time is 10s at 0.1 Torr and decreases to less than Is at 1.5 Torr. The nuclei grow and form three dimensional islands on S1O2, and as they coalesce, result in a rough surface morphology. At higher pressures, the inherent selectivity is lost resulting in a higher nucleation density and smoother surface morphology. For ˜ 2000 Å thick films, the root-mean-square surface roughness at 750ÅC ranges from 110Å at 0.1 Torr to 40Å at 1.5 Torr. Temperature also strongly influences the film structure through surface mobility and grain growth. At 1 Torr, the roughness ranges from 3Å at 625°C to 60Å at 750°C. The grain structure at 625°C/1Torr appears to be amorphous, whereas at 750°C the structure is columnar. The growth rate at 625°C/1.5 Torr is 1200 Å/min provides a surface roughness on the order of atomic dimensions which is comparable to or better than amorphous silicon deposited in LPCVD furnaces.

In-Process Diagnostic System for Semiconductor Materials Using UHV Wafer Transfer Chamber

1993 ◽  
Vol 324 ◽  
Author(s):  
F. Uchida ◽  
M. Matsui ◽  
H. Kakibayashi ◽  
M. Kouguchi ◽  
A. Mutoh ◽  
...  
Keyword(s):  
High Vacuum ◽  
Diagnostic System ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Vacuum System ◽  
Wafer Surface ◽  
Measuring Instruments ◽  
Ion Pump ◽  
Semiconductor Wafer ◽  
Chemical Conditions

AbstractWe have developed a novel stand-alone diagnostic system that can analyze a semiconductor wafer surface in each process without introducing contamination. This allows us to analyze the relationship between chemical conditions and device properties.A UHV (Ultra High Vacuum) wafer transfer chamber is used between the measuring apparatus and the semiconductor processes. The chamber vacuum system, which consists of a battery driven ion pump and a liquid N2 shroud, achieves a pressure of 2 × 10−8 Pa (corresponding to about 100 min. until one monolayer of contamination has been adsorbed).Wafer transfer lines have been constructed between semiconductor vacuum processes, CVD (Chemical Vapor Deposition) and measuring instruments, ESCA (Electron Spectroscopy for Chemical Analysis) and TEM (Transmission Electron Microscope). Our results from ESCA and TEM showed measurements that carbon contamination and oxidation was suppressed.

Aluminum Chemical Vapor Deposition Using Triisobutylaluminum: Mechanism, Kinetics, and Deposition Rates at Steady State

1988 ◽  
Vol 131 ◽  
Author(s):  
Brian E. Bent ◽  
Lawrence Dubois ◽  
Ralph G. Nuzzo
Keyword(s):  
Chemical Vapor Deposition ◽  
Kinetic Parameters ◽  
Gas Phase ◽  
Vapor Deposition ◽  
High Vacuum ◽  
Aluminum Atom ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Vacuum System ◽  
Aluminum Surface

ABSTRACTAn important step in the chemical vapor deposition (CVD) of aluminum from triisobutylaluminum (TIBA) is the reaction between TIBA (adsorbed from the gas phase) and the growing aluminum surface. We have studied this chemistry by impinging TIBA under collisionless conditions in an ultra-high vacuum system onto single crystal Al(111) and Al(100) substrates. We find that when TIBA (340K) collides with an aluminum surface heated to between 500 and 600K, the aluminum atom is cleanly abstracted from this precursor with near unit reaction probability to deposit, epitaxially, carbon-free aluminum films. The gas phase products are isobutylene and hydrogen. From monolayer thermal desorption experiments, we have determined the kinetic parameters for the rate-determining step, a β-hydride elimination reaction by surface bound isobutyl ligands. Using these kinetic parameters and a Langmuir absorption model, we can predict the rate of aluminum deposition at pressures ranging from 10−6 to 1 Torr.

The design and study of a compact bakeable ultra-high vacuum system for calibrating absolutely low pressure gauges

Vacuum ◽  
1977 ◽  
Vol 27 (9) ◽  
pp. 511-517 ◽  
Author(s):  
K.J. Close ◽  
R.S. Vaughan-Watkins ◽  
J Yarwood
Keyword(s):  
High Vacuum ◽  
Low Pressure ◽  
Ultra High Vacuum ◽  
Vacuum System

Challenge to 200 mm 3C-SiC Wafers Using SOI

2005 ◽  
Vol 483-485 ◽  
pp. 205-208 ◽  
Author(s):  
Motoi Nakao ◽  
Hirofumi Iikawa ◽  
Katsutoshi Izumi ◽  
Takashi Yokoyama ◽  
Sumio Kobayashi
Keyword(s):  
Cross Section ◽  
Vapor Deposition ◽  
Seed Layer ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Average Thickness ◽  
Entire Region ◽  
Transmission Electron ◽  
Good Crystallinity

200 mm wafer with 3C-SiC/SiO2/Si structure has been fabricated using 200 mm siliconon- insulator (SOI) wafer. A top Si layer of 200 mm SOI wafer was thinned down to approximately 5 nm by sacrificial oxidization, and the ultrathin top Si layer was metamorphosed into a 3C-SiC seed layer using a carbonization process. Afterward, an epitaxial SiC layer was grown on the SiC seed layer with ultra-high vacuum chemical vapor deposition. A cross-section transmission electron microscope indicated that a 3C-SiC seed layer was formed directly on the buried oxide layer of 200 mm wafer. The epitaxial SiC layer with an average thickness of approximately 100 nm on the seed was recognized over the entire region of the wafer, although thickness uniformity of the epitaxial SiC layer was not as good as that of SiC seed layer. A transmission electron diffraction image of the epitaxial SiC layer showed a monocrystalline 3C-SiC(100) layer with good crystallinity. These results indicate that our method enables to realize 200 mm SiC wafers.

Ultra-high vacuum chemical vapor deposition and in situ characterization of titanium oxide thin films

1991 ◽  
Vol 6 (9) ◽  
pp. 1913-1918 ◽  
Author(s):  
Jiong-Ping Lu ◽  
Rishi Raj
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Titanium Oxide ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Titanium Isopropoxide ◽  
Ultra High Vacuum

Chemical vapor deposition (CVD) of titanium oxide films has been performed for the first time under ultra-high vacuum (UHV) conditions. The films were deposited through the pyrolysis reaction of titanium isopropoxide, Ti(OPri)4, and in situ characterized by x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). A small amount of C incorporation was observed during the initial stages of deposition, through the interaction of precursor molecules with the bare Si substrate. Subsequent deposition produces pure and stoichiometric TiO2 films. Si–O bond formation was detected in the film-substrate interface. Deposition rate was found to increase with the substrate temperature. Ultra-high vacuum chemical vapor deposition (UHV-CVD) is especially useful to study the initial stages of the CVD processes, to prepare ultra-thin films, and to investigate the composition of deposited films without the interference from ambient impurities.

Homoepitaxy of Ge on ozone-treated Ge (1 0 0) substrate by ultra-high vacuum chemical vapor deposition

2019 ◽  
Vol 507 ◽  
pp. 113-117 ◽  
Author(s):  
Jiaqi Wang ◽  
Limeng Shen ◽  
Guangyang Lin ◽  
Jianyuan Wang ◽  
Jianfang Xu ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum

scholarly journals Why Pressure Scales Cause So Much Confusion

1993 ◽  
Vol 1 (8) ◽  
pp. 5-6
Author(s):  
Anthony D. Buonaquisti
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Ambient Pressure ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Vacuum System ◽  
Scanning Auger Microprobe ◽  
The Mean ◽  
Scanning Electron

Pressure scales can be extremely confusing to new operators. This is not surprising. To my mind, there are three primary areas of confusion.Firstly, the pressure of gas inside an instrument changes over many orders of magnitude during pumpdown. The change is about 9 orders of magnitude for a traditional Scanning Electron Microscope and about 13 orders of magnitude for an ultra-high vacuum instrument such as a Scanning Auger Microprobe.To give an idea about the scale of change involved in vacuum, consider that the change in going from ambient pressure to that inside a typical ultra high vacuum system is like comparing one meter with the mean radius of the planet Pluto's orbit. The fact is that we don't often get to play with things on that scale. As a consequence, many of us have to keep reminding ourselves that 1 X 10-3 is one thousand times the value of 1 X 10-6 - not twice the value.

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