A Kinetic Analysis of the Growth and Doping Kinetics of the SiC Chemical Vapor Deposition Process

Cavallotti, Carlo; Rossi, Filippo; Ravasio, Stefano; Masi, Maurizio

doi:10.1021/ie403907w

Cited by 15 publications

(10 citation statements)

References 53 publications

(115 reference statements)

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“…11 The same route applies to SiHCl 3 as precursor, albeit the first step is missing. If instead SiH 4 is used, the reactions proceed in the opposite direction by first forming SiH 2 + H 2 , and then SiH 2 + HCl → SiH 3 Cl, which then turns into SiH 2 Cl 2 and SiHCl 3 via reactions with HCl, producing H 2 .…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Finding the Optimum Chloride-Based Chemistry for Chemical Vapor Deposition of SiC

Yazdanfar

Danielsson

Kordina

et al. 2014

ECS J. Solid State Sci. Technol.

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Chemical vapor deposition of silicon carbide with a chloride-based chemistry can be done using several different silicon and carbon precursors. Here, we present a comparative study of SiCl 4 , SiHCl 3 , SiH 4 +HCl, C 3 H 8 , C 2 H 4 and CH 4 in an attempt to find the optimal precursor combination. We find that while the chlorinated silanes SiCl 4 and especially SiHCl 3 give higher growth rate than natural silane and HCl, SiH 4 +HCl gives better morphology at C/Si around 1 and SiCl 4 gives the best morphology at low C/Si. Our study shows no effect on doping incorporation with precursor chemistry. We suggest that these results can be explained by the number of reaction steps in the gas phase chemical reaction mechanisms for producing SiCl 2 , which is the most important Si species, and by formation of organosilicons in the gas phase. As carbon precursor, C 3 H 8 or C 2 H 4 are more or less equal in performance with a slight advantage for C 3 H 8 , CH 4 is however not a carbon precursor that should be used unless extraordinary growth conditions are For the last, approximately ten years, chloride-based chemistry has been studied for chemical vapor deposition (CVD) of electronic grade SiC.1 The addition of Cl to the gas mixture circumvents condensation of silicon droplets above the substrate since the stronger Si-Cl bond (400 kJ/mol or 4.15 eV) 2 prevents Si-Si bonds (226 kJ/mol or 2.34 eV) 2 to form. This allows a higher precursor concentration in the CVD gas mixture which enables higher growth rates of epitaxial SiC layers; growth rates exceeding 100 μm/h are common, compared to the 5-10 μm/h usually obtained for the standard, non-chlorinated chemistry based on silane (SiH 4 ) and small hydrocarbons like ethylene (C 2 H 4 ) or propane (C 3 H 8 ). Cl-based CVD chemistry is therefore seen as an enabler of SiC power device technology 1 , where approximately 100 μm thick, low doped (10 14 cm −3 ), epitaxial layers are required for devices capable of blocking voltages on the order of 10 kV.Addition of Cl can be done either through the addition of HCl to the standard precursors, by using a chlorinated silane molecule (SiH x Cl y ) instead of SiH 4 , by using a chlorinated hydrocarbon (CH x Cl y ) instead of C 3 H 8 /C 2 H 4 or by using a single molecule (SiH x C y Cl z ). All these approaches have been reported to be successful and capable of growth rates exceeding 100 μm/h. 1 However, the optimal precursor for Clbased CVD of SiC is still not identified, despite ten years of research on Cl-based CVD chemistry. The single molecule approach has been successful, 3 but the inherent locked C/Si ratio hinders an efficient control of the doping incorporation 4 in SiC. Thermochemical studies suggests that the use of CH x Cl y is not likely an optimal route since the C-Cl bond is found to break, allowing Si-Cl bonds to form.5 Thus the CH x Cl y approach is probably a chemical detour. There have been attempts to compare data from various groups 1,6 but these comparisons are hampered by the fact that the data are acquired in differ...

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Section: Resultsmentioning

confidence: 99%

“…• off-cut toward the [11][12][13][14][15][16][17][18][19][20] direction. All growth experiments were done on the Si-face of the substrate.…”

Section: Methodsmentioning

confidence: 99%

Finding the Optimum Chloride-Based Chemistry for Chemical Vapor Deposition of SiC

Yazdanfar

Danielsson

Kordina

et al. 2014

ECS J. Solid State Sci. Technol.

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“…Doping of SiC Crystals during Sublimation Growth and Diffusion DOI: http://dx.doi.org /10.5772/intechopen.82346 In this method high efficiency of impurity mass transfer is reached that is difficult to realize in other gas transport techniques, for example CVD [17].…”

Section: Sic Doping During Sublimation Growthmentioning

confidence: 99%

Doping of SiC Crystals during Sublimation Growth and Diffusion

Мохов¹

2019

Crystal Growth

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The preparation of SiC crystals doped with various impurities introduced during the process of sublimation growth and diffusion is described. The growth of SiC crystals was carried out by a sublimation-sandwich method, proposed by us in 1970. Crystals of the n-and p-type conductivity with maximum content of electrically active impurities (of the order of 10 21 cm −3) were obtained. The solubility values of more than 15 impurities were determined. Special tantalum containers with several temperature zones, allowing to introduce any impurity into SiC practically, are developed. The dependences of the impurities concentration on the temperature, growth rate and seed orientation are found. Diffusion of impurities of boron, aluminum, gallium, beryllium, lithium, nitrogen and phosphorus in silicon carbide polytypes was studied. Diffusion coefficients of these impurities in a wide temperature range are determined. It is shown that for a number of impurities diffusion cannot be described by standard distributions that are explained by the presence of several states of diffusing centers. Fast-diffusing states are atoms located in interstices, as well as centers, including the impurity atom and point defect. The extremely low diffusion mobility of lattice point atoms in the SIC lattice is noted.

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“…For the chlorinated chemistry is has been suggested by Cavallotti et al that SiN is an important N dopant species. 17 In the fluorinated chemistry the Si species is not formed in high concentrations. 15 Together with the stable N2 molecule another reason for the increasing dopant incorporation along the gas flow can be that the kinetics of forming N dopant species is slow, thereby forming more such species downstream, creating a higher dopant concentration downstream.…”

Section: A N-type Doping Using N2mentioning

confidence: 99%

Incorporation of dopants in epitaxial SiC layers grown with fluorinated CVD chemistry

Stenberg

Janzén

Pedersen

2017

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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Fluorinated chemistry in chemical vapor deposition (CVD) of silicon carbide (SiC) with SiF4 as Si precursor has been shown to fully eliminate the formation of silicon clusters in the gas phase, making SiF4 an interesting Si precursor. However, before a fluorinated CVD chemistry can be adopted, the effect of fluorine on the dopant incorporation must be understood since dopant incorporation is of paramount importance in semiconductor manufacturing. Here, the authors present dopant incorporation studies for n-type doping with N using N2 and p-type doping with Al using TMAl in fluorinated CVD of homoepitaxial SiC. The precursors used were SiF4 as Si precursor and the source of F together with CH4 as C precursor. The authors find that it is possible to control the doping in SiC epitaxial layers when using a fluorinated CVD chemistry for both n- and p-type materials using the C/Si ratio as in standard SiC CVD. However, large area doping uniformity seems to be a challenge for a fluorinated CVD chemistry, most likely due to the very strong Si–F and Al–F bonds.

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A Kinetic Analysis of the Growth and Doping Kinetics of the SiC Chemical Vapor Deposition Process

Cited by 15 publications

References 53 publications

Finding the Optimum Chloride-Based Chemistry for Chemical Vapor Deposition of SiC

Finding the Optimum Chloride-Based Chemistry for Chemical Vapor Deposition of SiC

Doping of SiC Crystals during Sublimation Growth and Diffusion

Incorporation of dopants in epitaxial SiC layers grown with fluorinated CVD chemistry

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