Chemical Vapor Deposition

Ohring, Milton

doi:10.1016/b978-012524975-1/50009-4

Cited by 136 publications

(261 citation statements)

References 37 publications

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“…This leads to the generation of point defects in the atomic layers of the GaN during the collision cascade from the energetic bombarding species. 30 This process is also known as atomic peening. This induces the observed mottled contrast in TEM and the isotropic strain component revealed by HRXRD.…”

Section: Resultsmentioning

confidence: 99%

Two-domain formation during the epitaxial growth of GaN (0001) on c-plane Al2O3 (0001) by high power impulse magnetron sputtering

Junaid

Lundin

Pališaitis

et al. 2011

Journal of Applied Physics

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We study the effect of high power pulses in reactive magnetron sputter epitaxy on the structural properties of GaN (0001) thin films grown directly on Al2O3 (0001) substrates. The epilayers are grown by sputtering from a liquid Ga target, using a high power impulse magnetron sputtering power supply in a mixed N2/Ar discharge. X-ray diffraction, micro-Raman, micro-photoluminescence, and transmission electron microscopy investigations show the formation of two distinct types of domains. One almost fully relaxed domain exhibits superior structural and optical properties as evidenced by rocking curves with a full width at half maximum of 885 arc sec and a low temperature band edge luminescence at 3.47 eV with the full width at half maximum of 10 meV. The other domain exhibits a 14 times higher isotropic strain component, which is due to the higher densities of the point and extended defects, resulting from the ion bombardment during growth. Voids form at the domain boundaries. Mechanisms for the formation of differently strained domains, along with voids during the epitaxial growth of GaN are discussed.

funding agencies|Swedish Foundation for Strategic Research||

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Section: Resultsmentioning

confidence: 99%

Two-domain formation during the epitaxial growth of GaN (0001) on c-plane Al2O3 (0001) by high power impulse magnetron sputtering

Junaid

Lundin

Pališaitis

et al. 2011

Journal of Applied Physics

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funding agencies|Swedish Foundation for Strategic Research||

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“…This discrepancy has been reported in the literature before 19 and may be due to (a) the analytical error from EDS (usually it has a 3% variation); (b) the actual amount of Fe and Ni in the FeNi target not being equal; (c) the sputtering process not being in the equilibrium state, at which the film materials would have the same composition of the target, particularly for the case of sputtering alloy. 20 Fig . 4 shows the XRD spectra of film materials deposited under the sputtering conditions listed in Table I.…”

Section: B Microstructure Characterizationmentioning

confidence: 99%

Development of FeNiMoB thin film materials for microfabricated magnetoelastic sensors

Cai

Gooneratne

Cha

et al. 2012

Journal of Applied Physics

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MetglasTM 2826MB foils of 25–30 μm thickness with the composition of Fe40Ni38Mo4B18 have been used for magnetoelastic sensors in various applications over many years. This work is directed at the investigation of ∼3 μm thick iron-nickel-molybdenum-boron (FeNiMoB) thin films that are intended for integrated microsystems. The films are deposited on Si substrate by co-sputtering of iron-nickel (FeNi), molybdenum (Mo), and boron (B) targets. The results show that dopants of Mo and B can significantly change the microstructure and magnetic properties of FeNi materials. When FeNi is doped with only Mo its crystal structure changes from polycrystalline to amorphous with the increase of dopant concentration; the transition point is found at about 10 at. % of Mo content. A significant change in anisotropic magnetic properties of FeNi is also observed as the Mo dopant level increases. The coercivity of FeNi films doped with Mo decreases to a value less than one third of the value without dopant. Doping the FeNi with B together with Mo considerably decreases the value of coercivity and the out-of-plane magnetic anisotropy properties, and it also greatly changes the microstructure of the material. In addition, doping B to FeNiMo remarkably reduces the remanence of the material. The film material that is fabricated using an optimized process is magnetically as soft as amorphous MetglasTM 2826MB with a coercivity of less than 40 Am−1. The findings of this study provide us a better understanding of the effects of the compositions and microstructure of FeNiMoB thin film materials on their magnetic properties.

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“…Large enough flakes would stick and stay at the surface, reminiscent of the critical-size nuclei in the common thin-film nucleation theory. 27 The smaller flakes would not adhere to the substrate strongly enough to sustain high-energy thermal vibrations and would leave the substrate, unless they happened to be near the stable flakes ("nuclei") that are already present at the surface and make bonds to them. Stacking of the flakes on top of each other is improbable because the out-of-plane bonding energy between the flakes is lower than their adhesion to the substrate, as in the case of SiO 2 , 28,29 impeding formation of the second layer.…”

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confidence: 99%

Noncatalytic chemical vapor deposition of graphene on high-temperature substrates for transparent electrodes

Sun

Cole

Lindvall

et al. 2012

Applied Physics Letters

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A noncatalytic chemical vapor deposition mechanism is proposed, where high precursor concentration, long deposition time, high temperature, and flat substrate are needed to grow large-area nanocrystalline graphene using hydrocarbon pyrolysis. The graphene is scalable, uniform, and with controlled thickness. It can be deposited on virtually any nonmetallic substrate that withstands ∼1000 o C. For typical examples, graphene grown directly on quartz and sapphire shows transmittance and conductivity similar to exfoliated or metalcatalyzed graphene, as evidenced by transmission spectroscopy and transport measurements. Raman spectroscopy confirms the sp 2 -C structure. The model and results demonstrate a promising transfer-free technique for transparent electrode production.Graphene, a monolayer of sp 2 carbon atoms, has received much attention. The use of graphene in transparent electronics is one of its most promising applications. 1 Apart from its high transparency/conductivity, the flexibility and ease of integration on a variety of substrates are obvious advantages. 30-inch graphene has been demonstrated by virtue of the recent advances in chemical vapor deposition (CVD), 2 which is compatible with the existing semiconductor technology. 3 Nevertheless, the necessity of etching the metal catalyst and transfer of graphene to foreign substrates hampers wide industrialization. Thus, efforts are put into the metal-free growth of graphene on materials including SiO 2 , 4-6 Al 2 O 3 , 7 MgO, 8 etc. To date, however, the graphitization process on dielectrics is poorly understood while the experiments are largely experience based. Recently, we have shown that large-area uniform graphene can be grown on virtually any hightemperature substrates, on Si 3 N 4 or HfO 2 , for instance. 9 In this letter, we provide a broader and deeper insight, discussing in detail the growth mechanism of graphene directly on insulators. As an example, we show our results on graphene on quartz and sapphire, hinting at the future prospects of the transfer-free graphene for transparent electrodes.Bulk graphite is usually made at >3000 o C and catalysis is needed to lower the temperature. 10 However, nanoscale graphene flakes form without any catalysts at merely ∼1000 o C. For example, carbon black which is produced massively by natural gas pyrolysis 11-14 is nothing else but chaotically connected graphene flakes. 11 Although widely used in industry, this process has so far been overlooked for making large-area graphene. Here, we show that macroscopically amorphous carbon black can be turned into textured graphene thin films when a) Electronic mail: jiesu@chalmers.se. the carbon precursor concentration and growth temperature are high, also requiring a relatively long deposition time and flat substrate. Fig. 1(a) illustrates the CVD reactor used in this work. The middle region is heated to 1000 o C while the left and right sides are <600 o C. There is no material deposition in the right zone because of the reduced CH 4 decomposition efficiency at lo...

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Chemical Vapor Deposition

Cited by 136 publications

References 37 publications

Two-domain formation during the epitaxial growth of GaN (0001) on c-plane Al2O3 (0001) by high power impulse magnetron sputtering

Two-domain formation during the epitaxial growth of GaN (0001) on c-plane Al2O3 (0001) by high power impulse magnetron sputtering

Development of FeNiMoB thin film materials for microfabricated magnetoelastic sensors

Noncatalytic chemical vapor deposition of graphene on high-temperature substrates for transparent electrodes

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