Polytypism and Properties of Silicon Carbide

Bechstedt, F.; Käckell, P.; Zywietz, A.; Karch, K.; Adolph, B.; Tenelsen, K.; Furthmüller, J.

doi:10.1002/1521-3951(199707)202:1<35::aid-pssb35>3.0.co;2-8

Cited by 243 publications

(164 citation statements)

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“…There are many different polytypes of SiC [8]. Each polytype can have a variety of possible defects, and furthermore each defect type may possess unique spin properties [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Electron spin coherence of silicon vacancies in proton-irradiated 4 H -SiC

et al. 2017

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We report T 2 spin coherence times for electronic states localized in Si vacancies in 4H-SiC. Our spin coherence study included two SiC samples that were irradiated with 2 MeV protons at different fluences (10 13 and 10 14 cm -2 ) in order to create samples with unique defect concentrations. Using optically detected magnetic resonance and spin echo, the coherence times for each sample were measured across a range of temperatures from 8 K to 295 K. All echo experiments were done at a magnetic field strength of 0.371 T and a microwave frequency of 10.49 GHz. The longest coherence times were obtained at 8 K, being 270 ± 61 µs for the 10 13 cm -2 proton-irradiated sample and 104 ± 17 µs for the 10 14 cm -2 sample. The coherence times for both samples displayed unusual temperature dependences; in particular, they decreased with temperature until 60 K, then increased until 160 K, then decreased again. This increase between 60 and 160 K is tentatively attributed to a motional Jahn-Teller effect. The consistently longer lifetimes for the 10 13 cm -2 sample suggest that a significant source of the spin dephasing can be attributed to dipole-dipole interactions between Si vacancies or with other defects produced by the proton irradiation. The lack of a simple exponential decay for our 10 14 cm -2 sample indicates an inhomogeneous distribution of defect spins.

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“…There are many different polytypes of SiC [8]. Each polytype can have a variety of possible defects, and furthermore each defect type may possess unique spin properties [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Electron spin coherence of silicon vacancies in proton-irradiated 4 H -SiC

et al. 2017

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“…SiC crystallizes in over 200 polytypes [1,2] with different Si-C stacking sequences. The most common polytypes are the 3C (Cubic) or β and 6H (Hexagonal) or α-SiC [3] and have similar mechanical and thermal properties but different electrical and optical properties.…”

Section: Silicon Carbidementioning

confidence: 53%

Fracture Toughness Evaluation and Plastic Behavior Law of a Single Crystal Silicon Carbide by Nanoindentation

2018

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Nanoindentation-based fracture toughness measurements of ceramic materials like silicon carbide (SiC) with pyramidal indenters are of significant interest in materials research. A majority of currently used fracture toughness models have been developed for Vickers indenters and are limited to specific crack geometries. The validity of the indentation-cracking method for the fracture toughness measurement of single crystal SiC, the elastic-plastic anisotropy and orientation dependence around the c-axis when indented in the <0001> direction is examined using nanoindentation with different pyramidal indenters. The residual impressions are analyzed using scanning electron microscopy to measure the crack lengths and the validity of existing fracture toughness measurement methods and equations is analyzed. A combination of nanoindentation with different pyramidal indenters to produce a wide range of effective strains and finite element simulation is used to extract flow properties of single crystal SiC in the <0001> direction. It is observed that there is no orientation dependence around the c-axis when SiC-6H is indented in the <0001> direction with a Berkovich indenter, i.e., it is transversely isotropic. It is also found that for a Berkovich indenter, the Jang and Pharr model, which is based on the Lawn model for cone/halfpenny cracks, gives approximately constant values at low loads (<1 N), while at higher loads (>1 N), the Laugier model gives constant fracture toughness values. Finite element analysis using equivalent cones is used along with measured hardness values to estimate the yield strength, the work hardening exponents and the stress-strain curve for single crystal SiC-6H in the <0001> direction.

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“…Pseudomorphic 3C-SiC layers were grown on α-SiC; they were unintentionally doped (as deduced by optical measurements) and nearly free of twins. Furthermore, the growth of other 4H/3C/4H heterostructures was also demonstrated, whose optical properties could be explained on the basis of theoretical calculations of the band structure of such systems [145,146].…”

Section: Interfaces Considering Different Sic Polytypesmentioning

confidence: 99%

Nanoscale transport properties at silicon carbide interfaces

Roccaforte¹,

Giannazzo²,

Raineri³

2010

J. Phys. D: Appl. Phys.

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Abstract. Wide band gap semiconductors promise devices with performances not achievable using silicon technology. Among them, Silicon Carbide (SiC) is considered the top-notch material for a new generation of power electronic devices, ensuring the improved energy efficiency requested in the modern society. In spite of the significant progresses achieved in the last decade in the material quality, there are still several scientific open issues related to the basic transport properties at SiC interfaces and ion-doped regions that can affect the devices performances, keeping them still far from their theoretical limits. Hence, significant efforts in fundamental research at nanoscale have become mandatory to better understand the carrier transport phenomena, both at surfaces and interfaces. In this paper, the most recent experiences on nanoscale transport properties will be addressed, reviewing the relevant key points for the basic devices building blocks. The selected topics include the major concerns related to the electronic transport in metal/SiC interfaces, to the carrier concentration and mobility in ion-doped regions, and to channel mobility in metal/oxide/SiC systems. Some aspects related to interfaces between different SiC polytypes are also presented. All these issues will be discussed considering the current status and the drawbacks of SiC devices.

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Polytypism and Properties of Silicon Carbide

Cited by 243 publications

References 0 publications

Electron spin coherence of silicon vacancies in proton-irradiated 4 H -SiC

Electron spin coherence of silicon vacancies in proton-irradiated 4 H -SiC

Fracture Toughness Evaluation and Plastic Behavior Law of a Single Crystal Silicon Carbide by Nanoindentation

Nanoscale transport properties at silicon carbide interfaces

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