| 1. |
- Abt, I, et al.
(författare)
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Inclusive V-0 production cross sections from 920 GeV fixed target proton-nucleus collisions
- 2003
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 29:2, s. 181-190
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Tidskriftsartikel (refereegranskat)abstract
- Inclusive differential cross sections dsigma(pA)/dx(F) and dsigma(pA)/dp(t)(2) for the production of K-S(0), Lambda, and (&ULambda;) over bar particles are measured at HERA in proton-induced reactions on C, Al, Ti, and W targets. The incident beam energy is 920 GeV, corresponding to roots = 41.6 GeV in the proton-nucleon system. The ratios of differential cross sections dsigma(pA)(K-S(0))/dsigma(pA)(Lambda) and dsigma(pA)((&ULambda;) over bar)/dsigma(pA) (Lambda) are measured to be 6.2 +/- 0.5 and 0.66 +/- 0.07, respectively, for x(F) approximate to -0.06. No significant dependence upon the target material is observed. Within errors, the slopes of the transverse momentum distributions da,Ald t also show no significant dependence upon the target material. The dependence of the extrapolated total cross sections sigma(pA) on the atomic mass A of the target material is discussed, and the deduced cross sections per nucleon sigma(pN) are compared with results obtained at other energies.
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| 2. |
- Abt, I, et al.
(författare)
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Measurement of the b(b)over-bar production cross section in 920 GeV fixed-target proton-nucleus collisions
- 2003
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 26:3, s. 345-355
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Tidskriftsartikel (refereegranskat)abstract
- Using the HERA-B detector, the b (b) over bar production cross section has been measured in 920 GeV proton collisions on carbon and titanium targets. The b (b) over bar production was tagged via inclusive bottom quark decays into J/psi by exploiting the longitudinal separation of J/psi --> l(+)l(-) decay vertices from the primary proton-nucleus interaction. Both e(+)e(-) and mu(+)mu(-) channels have been reconstructed and the combined analysis yields the cross section sigma(b (b) over bar) = 32(-12)(+14)(stat) (+6)(-7)(sys) nb/nucleon.
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| 3. |
- Frisk, U., et al.
(författare)
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The Odin satellite - I. Radiometer design and test
- 2003
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Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 402:3, s. L27-L34
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Tidskriftsartikel (refereegranskat)abstract
- The Sub-millimetre and Millimetre Radiometer (SMR) is the main instrument on the Swedish, Canadian, Finnish and French spacecraft Odin. It consists of a 1.1 metre diameter telescope with four tuneable heterodyne receivers covering the ranges 486-504 GHz and 541-581 GHz, and one fixed at 118.75 GHz together with backends that provide spectral resolution from 150 kHz to 1 MHz. This Letter describes the Odin radiometer, its operation and performance with the data processing and calibration described in Paper II.
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| 4. |
- Domeij, Martin, et al.
(författare)
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Measurements and simulations of self-heating and switching with 4H-SIC power BJTs
- 2003
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Ingår i: IEEE International Symposium on Power Semiconductor Devices and ICs (ISPSD). - Cambridge. ; , s. 375-378
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Konferensbidrag (refereegranskat)abstract
- Transient measurements and device simulations were performed to investigate self-heating and switching with 4H-SiC BJTs. A current gain decrease was found during self-heating presumably due to reduced electron mobility with increasing temperature. Surface recombination increased the simulated maximum temperature but the current gain decrease during self-heating was similar as for bulk recombination. A fast switching of 0.5 A and 200 V was shown with a voltage rise-time of about 70 ns and fall-time of 50 ns. Turn-off measurements show a noticeable delay time before fall-off of the emitter current, indicating a significant amount of stored carriers in the base.
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| 5. |
- G.M.Kalvius, F.E.Wagner, D.R.Noakes, E.Schreier, R.Wäppling, U.Zimmermann, W.Schafer, W.Kockelmann, I.Halevy, J.Gal
(författare)
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Magnetic behavior of YFe/sub x/Al/sub 12-x
- 2003
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Ingår i: Physica B. ; 326:1-4, s. 460-464
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Tidskriftsartikel (refereegranskat)
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| 6. |
- 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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| 7. |
- Linnarsson, M K, et al.
(författare)
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Precipitate formation in heavily Al-doped 4H-SiC layers
- 2001
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Ingår i: Materials Science Forum, Vols. 353-356. ; , s. 583-586, s. 583-586
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Konferensbidrag (refereegranskat)abstract
- Epitaxially grown 4H-SiC structures with several heavily Al doped layers were used. The samples were annealed in Ar atmosphere in a RF-heated furnace between 1500 and 2900 degreesC for 0.5 to 3h. Secondary ion mass spectrometry (SIMS) was used to measure the aluminum concentration versus,depth as well as the lateral distribution (ion images). Transmission electron microscopy (TEM) was employed to study the crystallinity and determine phase composition after heat treatment. A solubility limit of 2x10(20) Al/cm(3) at 2000 degreesC is extracted. Ion images of the lateral Al distribution reveal a pronounced dependence on the Al content. Precipitate formation occurs after heat treatment at 1700 - 2000 degreesC when the Al concentration exceeds 2x10(20) cm(-3) and energy-filtered TEM (EFTEM) shows that the precipitates contain Al.
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| 8. |
- Linnarsson, Margareta K., et al.
(författare)
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Solubility limit and precipitate formation in Al-doped 4H-SiC epitaxial material
- 2001
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 79:13, s. 2016-2018
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Tidskriftsartikel (refereegranskat)abstract
- Heavily Al-doped 4H-SiC structures have been prepared by vapor phase epitaxy. Subsequent anneals have been carried out in an Ar atmosphere in a rf-heated furnace between 1500 degreesC and 2000 degreesC for 0.5 to 3 h. Secondary ion mass spectrometry has been utilized to obtain Al concentration versus depth as well as lateral distributions (ion images). Transmission electron microscopy (TEM) has been employed to study the crystallinity and determine phase composition after heat treatment. A solubility limit of similar to 2x10(20) Al/cm(3) (1900 degreesC) is extracted. Three-dimensional ion images show that the Al distribution does not remain homogeneous in layers heat treated at 1700 degreesC or above when the Al concentration exceeds 2x10(20) cm(-3). Al-containing precipitates are identified by energy-filtered TEM.
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| 9. |
- Linnarsson, Margareta K., et al.
(författare)
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Solubility limits of dopants in 4H-SiC
- 2003
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Ingår i: Applied Surface Science. - 0169-4332 .- 1873-5584. ; 203, s. 427-432
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Tidskriftsartikel (refereegranskat)abstract
- Epitaxial 4H-SiC structures with heavily boron or aluminium doped layers have been prepared by vapour phase epitaxy. The samples have been annealed in Ar atmosphere in an RF-heated furnace between 1700 and 2000 degreesC for 45 min to 64 h. Secondary ion mass spectrometry has been employed to obtain depth distributions as well as lateral distributions (ion imaging) for boron and aluminium. Transmission electron microscopy has been used to study the crystallinity and determine phase composition. Solubility limits of similar to 1 x 10(20) Al/cm(3) (1700 degreesC) and < 1 x 10(20) B/cm(3) (1900 degreesC) have been deduced.
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| 10. |
- Osterman, J., et al.
(författare)
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Scanning spreading resistance microscopy of aluminum implanted 4H-SiC
- 2003
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Ingår i: Materials Science & Engineering. - 0921-5107 .- 1873-4944. ; 102:1-3, s. 128-131
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Results from the application of scanning spreading resistance microscopy (SSRM) for characterization of aluminum implanted 4H-SiC are presented. The implanted profiles are investigated electrically and morphologically as a function of post-implantation anneal conditions. The method is shown to be advantageous for measuring and optimizing the activation in many aspects with respect to existing alternative techniques: it provides information of the entire depth and Al concentration range, it is unaffected by annealing induced re-growth and/or surface roughening, and requires little sample preparation. The results indicate that the apparent activation and surface roughness do not saturate in the investigated temperature range of 1500-1650 °C. Finally, an apparent activation energy for the process of 3 eV is estimated. © 2003 Elsevier B.V. All rights reserved.
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