SiC-4H Epitaxial Layer Growth Using Trichlorosilane (TCS) as Silicon Precursor

2006 ◽  
Vol 527-529 ◽  
pp. 179-182 ◽  
Author(s):  
Stefano Leone ◽  
Marco Mauceri ◽  
Giuseppe Pistone ◽  
Giuseppe Abbondanza ◽  
F. Portuese ◽  
...  
Keyword(s):  
Growth Rate ◽  
Surface Roughness ◽  
Epitaxial Layer ◽  
Growth Rates ◽  
High Growth ◽  
Droplet Formation ◽  
Layer Growth ◽  
Crystal Quality ◽  
Epitaxial Layers ◽  
Carbon Precursor

4H-SiC epitaxial layers have been grown using trichlorosilane (TCS) as the silicon precursor source together with ethylene as the carbon precursor source. A higher C/Si ratio is necessary compared with the silane/ethylene system. This ratio has to be reduced especially at higher Si/H2 ratio because the step-bunching effect occurs. From the comparison with the process that uses silane as the silicon precursor, a 15% higher growth rate has been found using TCS (trichlorosilane) at the same Si/H2 ratio. Furthermore, in the TCS process, the presence of chlorine, that reduces the possibility of silicon droplet formation, allows to use a high Si/H2 ratio and then to reach high growth rates (16 *m/h). The obtained results on the growth rates, the surface roughness and the crystal quality are very promising.

Very High Growth Rate of 4H-SiC Using MTS as Chloride-Based Precursor

2008 ◽  
Vol 600-603 ◽  
pp. 115-118 ◽  
Author(s):  
Henrik Pedersen ◽  
Stefano Leone ◽  
Anne Henry ◽  
Franziska Christine Beyer ◽  
Vanya Darakchieva ◽  
...  
Keyword(s):  
Growth Rate ◽  
Linear Dependence ◽  
Growth Rates ◽  
Molar Fraction ◽  
High Growth ◽  
High Growth Rate ◽  
Epitaxial Layers ◽  
Single Precursor ◽  
Very High

The chlorinated precursor methyltrichlorosilane (MTS), CH3SiCl3, has been used to grow epitaxial layers of 4H-SiC in a hot wall CVD reactor, with growth rates as high as 170 µm/h at 1600°C. Since MTS contains both silicon and carbon, with the C/Si ratio 1, MTS was used both as single precursor and mixed with silane or ethylene to study the effect of the C/Si and Cl/Si ratios on growth rate and doping of the epitaxial layers. When using only MTS as precursor, the growth rate showed a linear dependence on the MTS molar fraction in the reactor up to about 100 µm/h. The growth rate dropped for C/Si < 1 but was constant for C/Si > 1. Further, the growth rate decreased with lower Cl/Si ratio.

SiC-4H Epitaxial Layer Growth by Trichlorosilane (TCS) as Silicon Precursor at Very High Growth Rate

2008 ◽  
Vol 600-603 ◽  
pp. 123-126 ◽  
Author(s):  
Francesco La Via ◽  
Gaetano Izzo ◽  
Marco Mauceri ◽  
Giuseppe Pistone ◽  
Giuseppe Condorelli ◽  
...  
Keyword(s):  
Growth Rate ◽  
Epitaxial Layer ◽  
Structural Characterization ◽  
Defect Density ◽  
Schottky Diodes ◽  
High Growth ◽  
High Growth Rate ◽  
Layer Growth ◽  
Characterization Methods ◽  
Very High

The growth rate of 4H-SiC epi layers has been increased up to 100 µm/h with the use of trichlorosilane instead of silane as silicon precursor. The epitaxial layers grown with this process have been characterized by electrical, optical and structural characterization methods. Schottky diodes, manufactured on the epitaxial layer grown with trichlorosilane at 1600 °C, have higher yield and lower defect density in comparison to diodes realized on epilayers grown with the standard epitaxial process.

Optimisation of Epitaxial Layer Growth with HCl Addition by Optical and Electrical Characterization

2007 ◽  
Vol 556-557 ◽  
pp. 137-140 ◽  
Author(s):  
Lucia Calcagno ◽  
Gaetano Izzo ◽  
Grazia Litrico ◽  
G. Galvagno ◽  
A. Firrincieli ◽  
...  
Keyword(s):  
Epitaxial Layer ◽  
Growth Process ◽  
Electrical Characterization ◽  
High Growth ◽  
High Growth Rate ◽  
Layer Growth ◽  
Epitaxial Layers ◽  
Electrical Measurements ◽  
Deposition Chamber ◽  
Order Of Magnitude

High growth rate of 4H-SiC epitaxial layers can be reached with the introduction of HCl in the deposition chamber. The effect of the Cl/Si ratio on this epitaxial growth process has been studied by optical and electrical measurements. Optical microscopy shows an improvement of the surface morphology and luminescence measurements reveal a decrease of epitaxial layer defects with increasing the Cl/Si ratio in the range 0.05–2.0. The leakage current measured on the diodes realized on these wafers is reduced of an order of magnitude and DLTS measurements show a decrease of the EH6,7 level concentration in the same range of Cl/Si ratio. The value Cl/Si=2.0 allows to grow epitaxial layers with the lowest defect concentration.

New SiC Epitaxial Growth Process with up to 100% BPD to TED Defect Conversion on 150mm Hot-Wall CVD Reactor

2019 ◽  
Vol 963 ◽  
pp. 123-126
Author(s):  
Tobias Höchbauer ◽  
Christian Heidorn ◽  
Nikolaos Tsavdaris
Keyword(s):  
Epitaxial Growth ◽  
Epitaxial Layer ◽  
Basal Plane ◽  
Growth Process ◽  
High Growth ◽  
High Growth Rate ◽  
Layer Growth ◽  
Structural Defects ◽  
Epitaxial Layers ◽  
Basal Plane Dislocation

The future challenges for SiC device technology are cost reduction and increased reliability. A key point to achieve that is the increase of yield during epitaxial layer growth through the reduction of structural defects (such as basal plane dislocations and triangle defects), an increased thickness and doping uniformity, and a high growth rate. Despite significant advancements in SiC epitaxial growth technology, it still constitutes a big challenge to find the optimum working point at which all those requirements are fulfilled. By implementing a new epitaxial layer growth process, we are able to grow basal plane dislocation free epitaxial layers, while the density of other structural defects remains low. Additionally, intra-wafer thickness and doping uniformities of the epitaxial layers are further improved.

Effects of Epitaxial Layer Growth Parameters on the Defect Density and on the Electrical Characteristics of Schottky Diodes

2005 ◽  
Vol 483-485 ◽  
pp. 429-432 ◽  
Author(s):  
Francesco La Via ◽  
Fabrizio Roccaforte ◽  
Salvatore di Franco ◽  
Alfonso Ruggiero ◽  
L. Neri ◽  
...  
Keyword(s):  
Growth Rate ◽  
Leakage Current ◽  
Epitaxial Layer ◽  
Defect Density ◽  
Growth Parameters ◽  
Schottky Diodes ◽  
Layer Growth ◽  
Epitaxial Layers ◽  
Low Leakage ◽  
Low Leakage Current

The effects of the Si/H2 ratio on the growth of the epitaxial layer and on the epitaxial defects was studied in detail. A large increase of the growth rate has been observed with the increase of the silicon flux in the CVD reactor. Close to a Si/H2 ratio of 0.05 % silicon nucleation in the gas phase occurs producing a great amount of silicon particles that precipitate on the wafers. The epitaxial layers grown with a Si/H2 ratio of 0.03% show a low defect density and a low leakage current of the Schottky diodes realized on these wafers. For these diodes the DLTS spectra show thepresence of several peaks at 0.14, 0.75, 1.36 and 1.43 eV. For epitaxial layers grown with higher values of the Si/H2 ratio and then with an higher growth rate, the leakage current of the Schottky diodes increases considerably.

Effects of the Growth Rate on the Quality of 4H Silicon Carbide Films for MOSFET Applications

2014 ◽  
Vol 778-780 ◽  
pp. 95-98 ◽  
Author(s):  
Massimo Camarda ◽  
Stefania Privitera ◽  
Ruggero Anzalone ◽  
Nicolò Piluso ◽  
Patrick Fiorenza ◽  
...  
Keyword(s):  
Growth Rate ◽  
Surface Roughness ◽  
Silicon Carbide ◽  
Surface Morphology ◽  
Growth Rates ◽  
Stacking Faults ◽  
High Growth ◽  
Mos Devices

In this paper we investigate the role of the growth rate (varied by changing the Si/H2ratio and using TCS to avoid Si droplet formation) on the surface roughness (Rq), the density of single Shockley stacking faults (SSSF) and 3C-inclusions (i.e. epi-stacking faults, ESF). We find that optimized processes with higher growth rates allow to improve the films inallthe considered aspects. This result, together with the reduced cost of growth processes, indicates that high growth rates should always be used to improve the overall quality of 4H-SiC homoepitaxial growths. Furthermore we analyze the connection between surface morphology and density of traps (Dit) at the SiO2/SiC interface in fabricated MOS devices finding consistent indications that higher surface roughness (step-bunched surfaces) can improve the quality of the interface by reducing theDitvalue.

Exploring SiC Growth Limitation of Vapor-Liquid-Solid Mechanism when Using Two Different Carbon Precursors

2013 ◽  
Vol 740-742 ◽  
pp. 323-326
Author(s):  
Kassem Alassaad ◽  
François Cauwet ◽  
Davy Carole ◽  
Véronique Soulière ◽  
Gabriel Ferro
Keyword(s):  
Growth Rate ◽  
High Growth ◽  
High Growth Rate ◽  
Carbon Precursor ◽  
Growth Limitation ◽  
Vapor Liquid Solid ◽  
Partial Pressures ◽  
Vapor Liquid Solid Mechanism ◽  
Vls Growth ◽  
Vapor Liquid

Abstract. In this paper, conditions for obtaining high growth rate during epitaxial growth of SiC by vapor-liquid-solid mechanism are investigated. The alloys studied were Ge-Si, Al-Si and Al-Ge-Si with various compositions. Temperature was varied between 1100 and 1300°C and the carbon precursor was either propane or methane. The variation of layers thickness was studied at low and high precursor partial pressure. It was found that growth rates obtained with both methane and propane are rather similar at low precursor partial pressures. However, when using Ge based melts, the use of high propane flux leads to the formation of a SiC crust on top of the liquid, which limits the growth by VLS. But when methane is used, even at extremely high flux (up to 100 sccm), no crust could be detected on top of the liquid while the deposit thickness was still rather small (between 1.12 μm and 1.30 μm). When using Al-Si alloys, no crust was also observed under 100 sccm methane but the thickness was as high as 11.5 µm after 30 min growth. It is proposed that the upper limitation of VLS growth rate depends mainly on C solubility of the liquid phase.

scholarly journals Rapid Growth of UropathogenicEscherichia coliduring Human Urinary Tract Infection

mBio ◽  
2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Valerie S. Forsyth ◽  
Chelsie E. Armbruster ◽  
Sara N. Smith ◽  
Ali Pirani ◽  
A. Cody Springman ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Urinary Tract ◽  
Growth Rates ◽  
High Growth ◽  
Replication Forks ◽  
Chromosomal Replication ◽  
E Coli ◽  
Tract Infections

ABSTRACTUropathogenicEscherichia coli(UPEC) strains cause most uncomplicated urinary tract infections (UTIs). These strains are a subgroup of extraintestinal pathogenicE. coli(ExPEC) strains that infect extraintestinal sites, including urinary tract, meninges, bloodstream, lungs, and surgical sites. Here, we hypothesize that UPEC isolates adapt to and grow more rapidly within the urinary tract than otherE. coliisolates and survive in that niche. To date, there has not been a reliable method available to measure their growth ratein vivo. Here we used two methods: segregation of nonreplicating plasmid pGTR902, and peak-to-trough ratio (PTR), a sequencing-based method that enumerates bacterial chromosomal replication forks present during cell division. In the murine model of UTI, UPEC strain growth was robustin vivo, matching or exceedingin vitrogrowth rates and only slowing after reaching high CFU counts at 24 and 30 h postinoculation (hpi). In contrast, asymptomatic bacteriuria (ABU) strains tended to maintain high growth ratesin vivoat 6, 24, and 30 hpi, and population densities did not increase, suggesting that host responses or elimination limited population growth. Fecal strains displayed moderate growth rates at 6 hpi but did not survive to later times. By PTR,E. coliin urine of human patients with UTIs displayed extraordinarily rapid growth during active infection, with a mean doubling time of 22.4 min. Thus, in addition to traditional virulence determinants, including adhesins, toxins, iron acquisition, and motility, very high growth ratesin vivoand resistance to the innate immune response appear to be critical phenotypes of UPEC strains.IMPORTANCEUropathogenicEscherichia coli(UPEC) strains cause most urinary tract infections in otherwise healthy women. While we understand numerous virulence factors are utilized byE. colito colonize and persist within the urinary tract, these properties are inconsequential unless bacteria can divide rapidly and survive the host immune response. To determine the contribution of growth rate to successful colonization and persistence, we employed two methods: one involving the segregation of a nonreplicating plasmid in bacteria as they divide and the peak-to-trough ratio, a sequencing-based method that enumerates chromosomal replication forks present during cell division. We found that UPEC strains divide extraordinarily rapidly during human UTIs. These techniques will be broadly applicable to measurein vivogrowth rates of other bacterial pathogens during host colonization.

An analysis of growth of different cattle genotypes reared in different environments

1984 ◽  
Vol 103 (1) ◽  
pp. 137-153 ◽  
Author(s):  
J. E. Frisch ◽  
T. E. Vercoe
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
High Growth ◽  
Environmental Stresses ◽  
Growth Potential ◽  
Gastrointestinal Helminths ◽  
Treatment Groups ◽  
Survival And Growth ◽  
Different Levels ◽  
High Growth Potential

SummaryCalves from three breeds, Brahman, Hereford × Shorthorn (HS) and Brahman × HS (BX), were divided equally into two groups, one of which was treated every 3 weeks from birth onwards to control ticks and gastrointestinal helminths, and one of which was untreated. Mortalities, growth rates and levels of resistance to environmental stresses that affected both mortality and growth under grazing conditions were recorded for all animals up to weaning (6 months) and for all males up to 15 months of age. The Brahmans were the most and the HS were the least resistant to environmental stresses, each of which was shown to depress growth in proportion to its magnitude and to contribute to the high mortalities of the HS. All breeds responded positively to parasite control with the greatest response in both survival and growth in the HS breed and the least response in the Brahman breed.Samples of males from the various breed-treatment groups were taken into pens where they were protected from environmental stresses and fed both low-quality pasture hay and high-quality lucerne hay ad libitum. Measurements were made of fasting metabolism, maintenance requirement, voluntary food intake and gain, variables related to the growth potential of each animal. The HS animals had the highest whilst the Brahmans had the lowest values for each variable.However, despite their low growth potential, the Brahmans had the highest growtli rate, and the HS, despite their high growth potential, had the lowest growth rate, when growth was measured in the presence of all environmental stresses. When parasites were controlled, growth rates were highest for the BX, the breed with intermediate growtli potential, and did not differ between the HS and Brahmans. These interactions arose because of the different contributions of resistance to environmental stresses and growth potential to growth rate measured at the different levels of environmental stresses. The relevance of these interactions to breed evaluation and cross-breeding is considered.Growth potential and resistance to environmental stresses were negatively correlated both between and within breeds, though the latter was biased by the effects of compensation. The influence of these relationships on the likely outcome of selection for increased growth rate, both between and within breeds, is discussed.

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