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| 2. |
- Hallen, A, et al.
(författare)
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Implanted p(+)n-junctions in silicon carbide
- 2003
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Ingår i: APPLICATION OF ACCELERATORS IN RESEARCH AND INDUSTRY. ; , s. 653-657
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Konferensbidrag (refereegranskat)abstract
- Ion implantation is considered a key technology for the realisation of silicon carbide electronic devices. Here we will give an overview of the field and present some recent results of ion implanted 4H SiC epitaxial layers. Mainly Al ions of keV energies have been used at different fluence, flux and target temperature. The samples have been investigated by secondary ion mass spectrometry (SIMS), channeling Rutherford backscattering (RBS-c) and transmission electron microscopy (TEM), both as-implanted and after annealing up to 1900 degreesC. Also the electrical activation of Al-implanted and annealed material has been investigated by scanning spreading resistance microscopy (SSRM). The damage accumulation, monitored by RBS-c, is linear with ion fluence but depends strongly on implantation temperature and ion flux. Annealing at temperatures above 1700 degreesC is needed to remove the damage and to electrically activate implanted Al ions. At these high annealing temperatures, however, dislocation loops are formed that have a negative influence on device performance.
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| 3. |
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| 4. |
- Kakanakova-Georgieva, Anelia, 1970-, et al.
(författare)
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Epitaxial growth of AlN layers on SiC substrates in a hot-wall MOCVD system
- 2002
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Ingår i: Phys. Stat. Sol. (c), Vol. 0, Issue 1. - : Wiley. ; , s. 205-208
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Konferensbidrag (refereegranskat)abstract
- In this study we report the successful growth of AlN and AlN/GaN on SiC substrates in a MOCVD process based on a hot-wall susceptor design. Different features of AlN growth are established depending on the total reactor pressure, temperature, off-cut SiC substrate orientation and V-to-III gas-flow ratio. The feasibility of the hot-wall MOCVD concept is demonstrated by the performance of AlN/GaN structures with state-of-the-art properties with strong potential for further optimization. A narrower X-ray rocking curve over the asymmetric 10.4 than the symmetric 00.2 reflection clearly underlines the high overall crystal quality of the GaN layers on AlN buffers grown in this type of MOCVD reactor.
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| 5. |
- Nordell, Nils, et al.
(författare)
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Boron implantation and epitaxial regrowth studies of 6H SiC
- 1998
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Ingår i: Journal of Electronic Materials. - : Springer Science and Business Media LLC. - 0361-5235 .- 1543-186X. ; 27:7, s. 833-837
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Tidskriftsartikel (refereegranskat)abstract
- Implantation of B has been performed into an epitaxially grown layer of 6H SiC, at two different B concentrations, 2 x 10(16) cm(-3) and 2 x 10(18) cm(-3). Subsequently, an epitaxial layer was regrown on the B implanted layer. The samples were investigated by transmission electron microscopy (TEM) and secondary ion mass spectrometry (SIMS). In the highly B-doped layers plate-like defects were found, associated with large strain fields, and an increased B concentration. These defects were stable at the originally implanted region during regrowth and at anneal temperatures up to 1700 degrees C. In the samples implanted with the lower B concentration, no crystal defects could be detected by TEM. No threading dislocations or other defects were observed in the regrown epitaxial layer, which shows the possibility to grow a layer with high crystalline quality on B implanted 6H SiC. By SIMS, it was found that B piles up at the interface to the regrown layer, which could be explained by enhanced diffusion from an increased concentration of point defects created by implantation damage in the region. B is also spread out into the original crystal and in the regrown layer at a concentration of below 2 x 10(16) cm(-3), with a diffusion constant estimated to 1.3 x 10(-12) cm(2)s(-1). This diffusion is most probably not driven by implantation damage, but by intrinsic defects in the grown crystal. Our investigation shows that the combination of implantation and subsequent regrowth techniques could be used in SiC for building advanced device structures, with the crystal quality in the regrown layer not being deteriorated by crystal defects in the implanted region. A device process using B implantation and subsequent regrowth could on the other hand be limited by the diffusion of B.
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| 6. |
- Persson, P.O.A., et al.
(författare)
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A solid phase reaction between Ti Cx thin films and Al2 O3 substrates
- 2008
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 103:6
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Tidskriftsartikel (refereegranskat)abstract
- Ti Cx thin films were deposited on Al2 O3 substrates at 900 °C by using a multiple cathode high current pulsed cathodic arc. The Ti:C pulse ratio and, hence, the composition was varied from C rich to Ti rich. It is found that the Al2 O3 substrate is decomposed and reacts with the Ti Cx film to incorporate significant amounts of O and Al in the growing film. When the stoichiometry is suitable, epitaxially oriented Ti2 AlC MAX phase with significant O incorporated is formed. The results indicate that Al2 O3 is not an ideal substrate material for the growth of transition metal carbides and MAX phase thin films. © 2008 American Institute of Physics.
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| 7. |
- Rosen, Johanna, et al.
(författare)
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Deposition of epitaxial Ti2AlC thin films by pulsed cathodic arc
- 2007
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Ingår i: Journal of Applied Physics. - : American Institute of Physics. - 0021-8979 .- 1089-7550. ; 101:5, s. 056101-
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Tidskriftsartikel (refereegranskat)abstract
- A multicathode high current pulsed cathodic arc has been used to deposit Ti2AlC thin films belonging to the group of nanolaminate ternary compounds of composition M(n+1)AX(n). The required stoichiometry was achieved by means of alternating plasma pulses from three independent cathodes. We present x-ray diffraction and transmission electron microscopy analysis showing that epitaxial single phase growth of Ti2AlC has been achieved at a substrate temperature of 900 degrees C. Our results demonstrate a powerful method for MAX phase synthesis, allowing for phase tuning within the M(n+1)AX(n) system.
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| 8. |
- Rosen, Johanna, et al.
(författare)
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Influence of gas entry point on plasma chemistry, ion energy and deposited alumina thin films in filtered cathodic arc
- 2007
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Ingår i: Plasma chemistry and plasma processing. - : Springer Science Business Media. - 0272-4324 .- 1572-8986. ; 27:5, s. 599-608
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Tidskriftsartikel (refereegranskat)abstract
- The effect of gas entry point on the plasma chemistry, ion energy distributions and resulting alumina thin film growth have been investigated for a d.c. cathodic arc with an aluminum cathode operated in an oxygen/argon atmosphere. Ions of aluminum, oxygen and argon, as well as ions originating from the residual gas are investigated, and measurements for gas entry at both the cathode and close to the substrate are compared. The latter was shown to result in higher ion flux, lower levels of ionised residual gas, and lower ion energies, as compared to gas inlet at the cathode. These plasma conditions that apply when gas entry at the substrate is used result in a higher film deposition rate, less residual gas incorporation, and more stoichiometric alumina films. The results show that the choice of gas entry point is a crucial parameter in thin film growth using reactive PVD processes such as reactive cathodic arc deposition.
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| 9. |
- Rosen, Johanna, et al.
(författare)
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Oxygen incorporation in Ti2AlC thin films
- 2008
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Ingår i: Applied Physics Letters. - : American Institute of Physics. - 0003-6951 .- 1077-3118. ; 92:6, s. 064102-
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Tidskriftsartikel (refereegranskat)abstract
- Thin films of Ti2AlC MAX phase have been deposited using a multiple cathode pulsed cathodic arc. Evidence for substantial oxygen incorporation in the MAX phase is presented, likely originating from residual gas present in the vacuum chamber during deposition. The characteristic MAX phase crystal structure is maintained, in agreement with ab initio calculations, supporting substitutional O in C lattice positions. On the basis of these results, we propose the existence of a MAX phase-like material with material properties tuned by the incorporation of oxygen. Additionally, possible unintentional O incorporation in previously reported MAX phase materials is suggested.
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