Search query: Investigation of SiC Polytypes

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abstract: It has been recognized that Raman scattering spectroscopy is a powerful tool to characterize SiC crystals non destructively. We review recent significant developments in the use of Raman scattering to study structural and electronic properties of SiC crystals. The areas to be discussed in the first part include polytype identification, evaluation of stacking disorder and ion implantation damages, and stress evaluation. The Raman scattering by electronic transitions is discussed in the second part of this article. We concentrate on the plasmon LO phonon coupled modes whose spectral profiles are used to evaluate the carrier concentration and mobility. Anisotropic electronic properties of a SiC and characteristics of heavily doped crystals are discussed. Semiconductor to metal transition and Fano interference effect are also treated.
author_names: Shin-ichi Nakashima

Hiroshi Harima
title: Raman Investigation of SiC Polytypes
year: 1997

author_names: Seong-Min Jeong

Ji-Young Yoon

Hyoung-Seuk Choi

Dae-Seop Byeon

Eun Jin Jung

Yong-Jin Kwon

Jae Whui Kim

Younghee Kim

Won Seon Seo

Myung-Hyun Lee
title: Investigation of SiC Polytypes for PVT Process Control Using Ultraviolet Fluorescence Technique
year: 2016

abstract: Spatially resolved high resolution electron energy loss in a high energy resolution monochromated EELS system (HERMES) system has attracted a lot of attention after its inception while opening new avenues of research and many unanswered questions. The recent advancements in EELS have made it possible for 1 nm probe sizes while still managing high probe current of around 10 pA [1] With this, spatially resolved transmission EELS is possible, paving the way for accurately quantifying bulk vibrational mode energies and distinguishing them from surface modes. [2] It is instructive to begin with a relatively simple system whose vibrational modes can be more precisely studied than other complex systems. We have chosen SiC as the system of choice due to its simple cubic structure in its 3C polytype and hexagonal structure in its 4H and 6H polytypes. Here we discuss only the SiC 6H polytype. SiC vibrational modes have been meticulously studies previously by means of Fourier transform infra red spectroscopy and Raman spectroscopy. With a well documented database for the SiC system, we hope to correlate our findings in spatially resolved high resolution EELS. Typically, Raman spectroscopy studies the surface vibrational modes of a material due to the low penetration depth of the laser. Although transmission Raman Spectroscopy [3] is capable of probing bulk modes in a material, it lacks the spatial resolution to map local bulk modes and study thickness and size dependent effects. With our HERMES system, we can show the distinction between surface and bulk modes in a thin high quality thin film single crystal sample as well as increase in scattering probability of bulk modes as a function of thickness.
author_names: Chaitanya A Gadre

Xingxu Yan

Xiaoqing Pan
title: Investigation of Surface and Bulk Vibrational Modes in SiC Polytypes using Spatially Resolved Monochromated HREELS
venue: Microscopy and Microanalysis
year: 2018

abstract: We calculated the hyperfine structure and the zero field splitting parameters of divacancies in 3C, 4H and 6H SiC in the ground state and in the excited state for 4H SiC within the framework of density functional theory. Besides that our calculations provide identification of the defect in different polytypes, we can find some carbon atoms next to the divacancy that of the spin polarizations are similar in the ground and excited states. This coherent nuclear spin polarization phenomenon can be the base to utilize 13C spins as quantum memory.
author_names: Krisztian Szasz

Viktor Ivady

Erik Janzen

Adam Gali
title: First Principles Investigation of Divacancy in SiC Polytypes for Solid State Qubit Application
year: 2014

abstract: A comprehensive study on the hydrogen etching of numerous SiC polytype surfaces and orientations has been performed in a hot wall CVD reactor under both atmospheric and low pressure conditions. The polytypes studied were 4H and 6H SiC as well as 3C SiC grown on Si substrates. For the hexagonal polytypes the wafer surface orientation was both on and off axis, i.e. C and Si face. The investigation includes the influence of the prior surface polishing method on the required etching process parameters. 3C SiC was also studied grown in both the (100) and (111) orientations. After etching, the samples were analyzed via atomic force microscopy (AFM) to determine the surface morphology and the height of the steps formed. For all cases the process conditions necessary to realize a well ordered surface consisting of unit cell and sub unit cell height steps were determined. The results of these experiments are summarized and samples of the corresponding AFM analysis presented.
author_names: Christopher L Frewin

Camilla Coletti

Christian Riedl

Ulrich Starke

Stephen E Saddow
title: A Comprehensive Study of Hydrogen Etching on the Major SiC Polytypes and Crystal Orientations
year: 2009

abstract: Raman spectroscopy was applied to investigate a series of SiC films grown on Si and 6H SiC substrates by a new method of solid gas phase epitaxy. During the growth characteristic voids are formed in Si at the SiC/Si interface. Raman peak position, intensity and linewidth were used to characterize the quality and the polytype structure of the SiC layers. A large enhancement in the peak intensity of the transverse optical and longitudinal optical phonon modes of SiC is observed for the Raman signal measured at the voids. In addition, scanning electron microscopy and atomic force microscopy were used to investigate the surface morphology of SiC layers.
author_names: Joanna Wasyluk

Tatiana Perova

Sergey A Kukushkin

Andrey V Osipov

N A Feoktistov

S A Grudinkin
title: Raman Investigation of Different Polytypes in SiC Thin Films Grown by Solid Gas Phase Epitaxy on Si (111) and 6H SiC Substrates
year: 2010

abstract: Among the various SiC polytypes, cubic 3C SiC is much more difficult to grow in high crystalline quality than the commercially introduced hexagonal 6H SiC and 4H SiC counterparts. Besides some benefits of 3C SiC for transistor applications related to a greater electron mobility and a lower metal oxide semiconductor interface trap density compared to 4H SiC, new potential optoelectronic applications have been introduced very recently. Boron doped 3C SiC may act as an ideal candidate for an intermediate band (IB) solar cell material. Aluminum doped p type 3C SiC could lead to the development of efficient optoelectrochemical water splitting cells. Finally, 3C SiC with its various intrinsic point defects has been considered as a suitable candidate for future spintronic applications. All these applications will critically depend on further understanding defect behaviour on atomic level. In our study we investigated free standing n type and p type 3C SiC material grown in our lab. Temperature dependent photoluminescence measurements revealed the presence of carbon vacancy related VC and VC CSi defect transitions in the p type materials but not in the n type materials. This observation present in as grown 3C SiC is believed to have significant impact on the optoelectronic applications. Copyright (c) 2017 VBRI Press.
author_names: Martin Wilhelm

Mikael Syvajarvi

Peter J Wellmann
title: Investigation of deep electronic levels in n type and p type 3C SiC using photoluminescence
year: 2017

abstract: SiC/AlN composites with controlled interfacial solid solution were employed in the present work for investigating the effects of interfacial bonding and AlN polytypes on the mechanical properties. Platelike AlN polytypes and interfacial bonding were found to have substantial effects on the flexural strength, hardness, and fracture toughness.
author_names: Jow-Lay Huang

Jyh-Ming Jih
title: Investigation of SiC AlN: Part II, Mechanical Properties
year: 1996

abstract: SiC/AlN composites with controlled interfacial solid solution were employed in this present work to investigate the effects of interfacial chemical composition and AlN polytypes on the fatigue properties. The dynamic strength of the SiC/AlN composite was found to decrease initially as the stressing rate decreased. However, the strength increased with a decrease in stress rate at a low stress rate region of below 0.01 MPa/s. Crack arrest could have occurred before exhibiting spontaneous failure at an intermediate stress rate of 0.01 MPa/s. It was found that both the interfacial bonding strength and testing technique had essential effects on the behavior of slow crack growth.
author_names: Jow-Lay Huang

Jyh-Ming Jih
title: Investigation of SiC AlN: Part III. Static and dynamic fatigue
year: 1995

abstract: Abstract Polytypes of colourless and coloured single crystals of silicon carbide (SiC) grown on SiC substrates by chemical vapour deposition are studied using Raman spectroscopy supplemented by scanning electron microscopy (SEM) and X ray diffraction (XRD) analyses. The SEM analysis of the defect stacking faults, inclusions of defects and their distribution has shown that they correlate with the peak positions of the obtained Raman spectra and with the XRD data on the crystal structure Kopsavilkums Dazadu fazu silicija karbida (SiC) monokristali, kas audzeti uz SiC pamatnem ar kimiskas nogulsnesanas metodi no gazveida fazes, tika petiti, izmantojot Ramana spektroskopiju, skenejoso elektronu mikroskopiju (SEM) un rentgenstaru difrakciju (XRD) Ar SEM palidzibu tika identificeti kristalografiskas strukturas apgabali un ieslegumi, ir pieradits, ka tie korele ar Ramana spektru piku pozicijam, un XRD datiem par kristalisko strukturu
author_names: Georg Chikvaidze

Nina Mironova-Ulmane

A V Plaude

O T Sergeev
title: Investigation of Silicon Carbide Polytypes by Raman Spectroscopy
year: 2014