Papers by Keyword: Heteroepitaxy

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Authors: Katja Tonisch, Wael Jatal, Ralf Granzner, Mario Kittler, Uwe Baumann, Frank Schwierz, Jörg Pezoldt
Abstract: We present the realization of high electron mobility transistors (HEMTs) based on AlGaN/GaN heterostructures grown on silicon substrates using a SiC transition layer. The growth of AlGaN/GaN heterostructures on Si (111) was performed using metalorganic chemical vapour deposition (MOCVD). The (111) SiC transition layer was realized by low pressure CVD and prevented Ga-induced meltback etching and Si-outdiffusion in the subsequent MOCVD growth. The two-dimensional electron gas (2DEG) formed at the AlGaN/GaN interface showed an electron sheet density of 1.5x1013 cm-3 and a mobility of 870 cm²/Vs proving the high structural quality of the heterostructure. Device processing was done using electron beam lithography. DC and RF characteristics were analysed and showed a peak cut-off frequency as high as 6 GHz for a 1.2 µm gate HEMT.
Authors: Thomas Kreiliger, Marco Mauceri, Marco Puglisi, Fulvio Mancarella, Francesco La Via, Danilo Crippa, Wlodek Kaplan, Adolf Schöner, Anna Marzegalli, Leo Miglio, Hans von Känel
Abstract: The growth morphology of epitaxial 3C-SiC crystals grown on hexagonal pillars deeply etched into Si (111) substrates is presented. Different growth velocities of side facets let the top crystal facet evolve from hexagonal towards triangular shape during growth. The lateral size and separation between Si pillars determine the onset of fusion between neighboring crystals during growth at a height tailoring of which is crucial to reduce the stacking fault (SF) density of the coalesced surface. Intermediate partial fusion of neighboring crystals is shown as well as a surface of fully coalesced crystals.
Authors: Christopher Locke, G. Kravchenko, P. Waters, J. D. Reddy, K. Du, A.A. Volinsky, Christopher L. Frewin, Stephen E. Saddow
Abstract: Single crystal 3C-SiC films were grown on (100) and (111) Si substrate orientations in order to study the resulting mechanical properties of this material. In addition, poly-crystalline 3C-SiC was also grown on (100)Si so that a comparison with monocrystaline 3C-SiC, also grown on (100)Si, could be made. The mechanical properties of single crystal and polycrystalline 3C-SiC films grown on Si substrates were measured by means of nanoindentation using a Berkovich diamond tip. These results indicate that polycrystalline SiC thin films are attractive for MEMS applications when compared with the single crystal 3C-SiC, which is promising since growing single crystal 3C-SiC films is more challenging. MEMS cantilevers and membranes fabricated from a 2 µm thick single crystal 3C-SiC grown on (100)Si under similar conditions resulted in a small degree of bow with only 9 µm of deflection for a cantilever of 700 µm length with an estimated tensile film stress of 300 MPa. Single crystal 3C-SiC films on (111)Si substrates have the highest elastic and plastic properties, although due to high residual stress they tend to crack and delaminate.
Authors: Giuseppe D'Arrigo, Andrea Severino, G. Milazzo, Corrado Bongiorno, Nicolò Piluso, Giuseppe Abbondanza, Marco Mauceri, Giuseppe Condorelli, Francesco La Via
Abstract: 3C-SiC devices are hampered by the defect density in heteroepitaxial films. Acting on the substrate, it is possible to achieve a better compliance between Si and 3C-SiC. We present here an approach to favorite defect geometrical reduction in both [ ] and [ ] directions by creating Inverted Silicon Pyramids (ISP). A study of 3C-SiC growth on ISP is reported showing benefits in the film quality and a reduction in the linear density of stacking faults. Growth on ISP leads also to a decrease in the 3C-SiC residual stress as well as in the bow of the Si/SiC system.
Authors: Ruggero Anzalone, Andrea Severino, Giuseppe D'Arrigo, Corrado Bongiorno, Patrick Fiorenza, Gaetano Foti, Giuseppe Condorelli, Marco Mauceri, Giuseppe Abbondanza, Francesco La Via
Abstract: The aim of this work is to improve the heteroepitaxial growth process of 3C-SiC on Si substrates using Trichlorosilane (SiHCl3) as the silicon growth precursor. With this precursor it has been shown that it is possible to simultaneously increase the growth rate of the process and avoid the nucleation of silicon droplets in the gas phase. Growth experiments were conducted on three (3) Si substrate orientations in order to assess the impact of the Si substrate on the resulting 3C-SiC film. X-ray Diffraction (XRD), Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) analysis show the important role of the substrate orientation for the growth process. The different orientation of the substrate modifies the morphology of the 3C-SiC crystalline structure, mostly by changing the density of micro-twins and stacking faults inside the film.
Authors: Anne Henry, Xun Li, Henrik Jacobson, Sven Andersson, Alexandre Boulle, Didier Chaussende, Erik Janzén
Abstract: The growth of 3C-SiC on hexagonal polytype is addressed and a brief review is given for various growth techniques. The Chemical Vapor Deposition is shown as a suitable technique to grow single domain 3C epilayers on 4H-SiC substrate and a 12.5 µm thick layer is demonstrated; even thicker layers have been obtained. Various characterization techniques including optical microscopy, X-ray techniques and photoluminescence are compared for the evaluation of the crystal quality and purity of the layers.
Authors: Arthur Vo-Ha, Mickaël Rebaud, Davy Carole, Mihai Lazar, Alexandre Tallaire, Véronique Soulière, Jose Carlos Pinero, Daniel Araújo, Gabriel Ferro
Abstract: This work deals with the localized epitaxial growth of SiC on (100) diamond substrate using the Vapour-Liquid-Solid (VLS) transport. An epitaxial relationship of grown SiC with the seed was succesfully achieved when inserting a silicidation step before the VLS growth. This silicidation consists in the formation of a SiC intermediate layer on the diamond substrate by solid-state reaction with a silicon layer deposited at 1000 or 1350 °C. On the 1350°C formed SiC buffer layer, p-doped 3C-SiC(100) islands elongated in the <110> directions were obtained after VLS growth. For the 1000°C buffer layer, the SiC deposit after VLS growth is much denser but mostly polycrystalline. Interfacial reactivity and diffusion are considered to explain the obtained results.
Authors: Hiroyuki Matsunami
Authors: Jörg Pezoldt, Bernd Schröter, Volker Cimalla, Thomas Stauden, R. Goldhahn, Henry Romanus, Lothar Spieß
Authors: Hiroyuki Nagasawa, Kuniaki Yagi, Takamitsu Kawahara, Naoki Hatta, Masayuki Abe, Adolf Schöner, Mietek Bakowski, Per Ericsson, Gerhard Pensl
Abstract: In 3C-SiC MOSFETs, planar defects like anti-phase boundaries (APBs) and stacking-faults (SFs) reduce the breakdown voltage and induce leakage current. Although the planar defect density can be reduced by growing 3C-SiC on undulant-Si substrate, specific type of SFs, which expose the Si-face, remains on the (001) surface. Those SFs increase the leakage current in devices made with 3C-SiC. In order to eliminate the residual SFs, an advanced SF reduction method involving polarity conversion and homo-epitaxial growth was developed. This method is called switch-back epitaxy (SBE) and consists of the conversion of the SF surface polarity from Si-face to C-face and following homo-epitaxial growth. The reduction of the SF density in SBE 3C-SiC results in a tremendous improvement of the device performance. The combination of the achieved blocking voltage with the demonstrated high current capability indicates the potential of 3C-SiC vertical MOSFETs for high and medium power electronic applications such as electric and hybrid electric vehicle (EV/HEV) motor drives.
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