| 1. |
- Mishra, A., et al.
(författare)
-
Stroke genetics informs drug discovery and risk prediction across ancestries
- 2022
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 611, s. 115-123
-
Tidskriftsartikel (refereegranskat)abstract
- Previous genome-wide association studies (GWASs) of stroke - the second leading cause of death worldwide - were conducted predominantly in populations of European ancestry(1,2). Here, in cross-ancestry GWAS meta-analyses of 110,182 patients who have had a stroke (five ancestries, 33% non-European) and 1,503,898 control individuals, we identify association signals for stroke and its subtypes at 89 (61 new) independent loci: 60 in primary inverse-variance-weighted analyses and 29 in secondary meta-regression and multitrait analyses. On the basis of internal cross-ancestry validation and an independent follow-up in 89,084 additional cases of stroke (30% non-European) and 1,013,843 control individuals, 87% of the primary stroke risk loci and 60% of the secondary stroke risk loci were replicated (P < 0.05). Effect sizes were highly correlated across ancestries. Cross-ancestry fine-mapping, in silico mutagenesis analysis(3), and transcriptome-wide and proteome-wide association analyses revealed putative causal genes (such as SH3PXD2A and FURIN) and variants (such as at GRK5 and NOS3). Using a three-pronged approach(4), we provide genetic evidence for putative drug effects, highlighting F11, KLKB1, PROC, GP1BA, LAMC2 and VCAM1 as possible targets, with drugs already under investigation for stroke for F11 and PROC. A polygenic score integrating cross-ancestry and ancestry-specific stroke GWASs with vascular-risk factor GWASs (integrative polygenic scores) strongly predicted ischaemic stroke in populations of European, East Asian and African ancestry(5). Stroke genetic risk scores were predictive of ischaemic stroke independent of clinical risk factors in 52,600 clinical-trial participants with cardiometabolic disease. Our results provide insights to inform biology, reveal potential drug targets and derive genetic risk prediction tools across ancestries.
|
|
| 2. |
- Khan, H.R., et al.
(författare)
-
A 900 MHz 26.8 dBm differential Class-E CMOS power amplifier in German Microwave Conference Digest of Papers, GeMIC 2010, vol , issue , pp 276-279
- 2010
-
Ingår i: German Microwave Conference Digest of Papers, GeMIC 2010. ; , s. 276-279
-
Konferensbidrag (refereegranskat)abstract
- A 900 MHz differential Class-E amplifier with finite dc inductance has been designed in CMOS. The large inductance of RF choke has been replaced with a finite inductance that provides the required inductive reactance of the class E amplifier. Resonance circuit is realized without series inductor by novel use of lattice LC balun. The amplifier delivers 26.8 dBm power to a 50 O load from a 2.2 V supply. A maximum Power Added Efficiency (PAE) of 43% is achieved.
|
|
| 3. |
- Ahuja, R., et al.
(författare)
-
Optical properties of 4H-SiC
- 2002
-
Ingår i: J. Appl. Phys.. ; 91:4, s. 2099-2103
-
Tidskriftsartikel (refereegranskat)
|
|
| 4. |
|
|
| 5. |
- Forsberg, U., et al.
(författare)
-
Growth and characterisation of 4H-SiC MESFET structures grown by hot-wall CVD
- 2001
-
Ingår i: Materials Research Society Symposium - Proceedings. - Boston, MA. ; , s. H2.3.1-H2.3.6
-
Konferensbidrag (refereegranskat)abstract
- Metal semiconductor field effect transistor, MESFET, structures have been grown in a hot-wall CVD reactor. Using trimethylaluminium and nitrogen as dopant sources, p- and n-type epitaxial layers were grown on semi insulating substrates. A comprehensive characterization study of thickness and doping of these structures has been performed by using scanning electron microscopy, secondary ion mass spectrometry, capacitance-voltage measurements. Each technique is discussed concerning its advantage and disadvantage. Some transistor properties of MESFETs processed on the grown material are presented.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Nordell, Nils, et al.
(författare)
-
Boron implantation and epitaxial regrowth studies of 6H SiC
- 1998
-
Ingår i: Journal of Electronic Materials. - : Springer Science and Business Media LLC. - 0361-5235 .- 1543-186X. ; 27:7, s. 833-837
-
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.
|
|
| 10. |
- Persson, P. O. Å, et al.
(författare)
-
Transmission electron microscopy investigation of defects in B-implanted 6H-SiC
- 1998
-
Ingår i: Silicon carbide, III-nitrides and related materials : ICSCIII-N'97. - : Trans Tech Publications Inc.. - 0878497900 ; , s. 413-416
-
Konferensbidrag (refereegranskat)abstract
- Silicon carbide is due to its wide bandgap, high saturated electron drift velocity, high electric breakdown field and high thermal conductivity a suitable material for electron devices operating at high temperatures, high powers and high frequencies.[1,2] In order for SIC to reach its full potential in device technology, doping is essential. Usually ion implantation is used for doping since diffusion is difficult in SiC. Boron is a useful material for implantation because of its low atomic weight and greater penetration depth than other accepters, yet very few studies have been conducted on B-implanted 6H-SiC. [3,4] In this investigation we have used transmission electron microscopy (TEM) to study structural defects that are found in B-implanted 6H-SiC layers.
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
- Willander, Magnus, 1948, et al.
(författare)
-
High-Temperature Electronic Materials: Silicon Carbide and Diamond
- 2007
-
Ingår i: Springer Handbooks. - Boston, MA : Springer US. ; , s. 537-563
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The physical and chemical properties of wide-band-gap semiconductors make these materials an ideal wide bandgapsemiconductor choice for device fabrication for applications in many different areas, e.g. light emitters, high-temperature and high-power electronics, high-power microwave devices, micro-electromechanical system (MEM) technology, and substrates for semiconductor preparation. These semiconductors have micro-electromechanical system (MEMS) been recognized for several decades as being suitable for these applications, but until recently the low material quality has not allowed the fabrication of high-quality devices. In this material quality chapter, we review the wide-band-gap semiconductors, silicon carbide and diamond. Silicon carbide electronics is advancing from the research stage to commercial production. The commercial availability of single-crystal SiC substrates during the early 1990s gave rise to intense activity in the development of silicon carbide devices. The commercialization started with the release of blue light-emitting diode (LED). The recent release of high-power Schottky diodes was a further demonstration of the progress made towards defect-free SiC substrates. Diamond has superior physical and chemical properties. Silicon-carbide- and diamond-based diamondsilicon carbide (SiC) electronics are at different stages of development. The preparation of high-quality single-crystal substrates of wafer size has allowed recent significant progress in the fabrication of several types of devices, and the development has reached many important milestones. However, high-temperature studies are still scarce, and diamond-based electronics is still in its infancy.
|
|
| 14. |
- Willander, Magnus, 1948-, et al.
(författare)
-
Invited : High tmeperature electronic materials Sic and Diamond
- 2006
-
Ingår i: Handbook of Electronic and Photonic Materials. - Boston : Spinger. - 0387260595 - 9780387260594 ; , s. -1406
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The Springer Handbook of Electronic and Photonic Materials has been prepared to give a broad coverage of a wide range of electronic and photonic materials, starting from fundamentals and building up to advanced topics and applications. Its wide coverage with clear illustrations and applications, its chapter sequencing and logical flow, make it very different than other electronic materials handbooks. Each chapter has been prepared either by experts in the field or instructors who have been teaching the subject at a university or in corporate laboratories. The handbook provides an accessible treatment of the material by developing the subject matter in easy steps and in a logical flow. Wherever possible, the sections have been logically sequenced to allow a partial coverage at the beginning of the chapter for those who only need a quick overview of the subject. Additional valuable features include the practical applications used as examples, details on experimental techniques, useful tables that summarize equations, and, most importantly, properties of various materials. The handbook also has an extensive glossary at the end being helpful to those readers whose background may not be directly in the field. Key Topics Fundamental Electronic, Optical and Magnetic Properties Materials Growth and Characterization Materials for Electronics Materials for Optoelectronics and Photonics Novel Materials Selected Applications Features Contains over 600 two-color illustrations Includes over 100 comprehensive tables summarizing equations, experimental techniques and properties of various materials Emphasizes physical concepts over extensive mathematical derivations Parts and chapters with summaries, detailed index and fully searchable CD-ROM guarantee quick access to data and links to other sources Delivers a wealth of up-to-date references Incorporates a detailed Glossary of Terms
|
|
| 15. |
- Willander, Magnus, 1948-, et al.
(författare)
-
Silicon carbide and diamond for high temperature device applications
- 2006
-
Ingår i: Journal of materials science. Materials in electronics. - : Springer Science and Business Media LLC. - 0957-4522 .- 1573-482X. ; 17:1
-
Tidskriftsartikel (refereegranskat)abstract
- The physical and chemical properties of wide bandgap semiconductors silicon carbide and diamond make these materials an ideal choice for device fabrication for applications in many different areas, e.g. light emitters, high temperature and high power electronics, high power microwave devices, micro-electromechanical system (MEMS) technology, and substrates. These semiconductors have been recognized for several decades as being suitable for these applications, but until recently the low material quality has not allowed the fabrication of high quality devices. Silicon carbide and diamond based electronics are at different stages of their development. An overview of the status of silicon carbide's and diamond's application for high temperature electronics is presented. Silicon carbide electronics is advancing from the research stage to commercial production. The most suitable and established SiC polytype for high temperature power electronics is the hexagonal 4H polytype. The main advantages related to material properties are: its wide bandgap, high electric field strength and high thermal conductivity. Almost all different types of electronic devices have been successfully fabricated and characterized. The most promising devices for high temperature applications are pn-diodes, junction field effect transistors and thyristors. MOSFET is another important candidate, but is still under development due to some hidden problems causing low channel mobility. For microwave applications, 4H-SiC is competing with Si and GaAs for frequency below 10 GHz and for systems requiring cooling like power amplifiers. The unavailability of high quality defect and dislocation free SiC substrates has been slowing down the pace of transition from research and development to production of SiC devices, but recently new method for growth of ultrahigh quality SiC, which could promote the development of high power devices, was reported. Diamond is the superior material for high power and high temperature electronics. Fabrication of diamond electronic devices has reached important results, but high temperature data are still scarce. PN-junctions have been formed and investigated up to 400 °C. Schottky diodes operating up to 1000 °C have been fabricated. BJTs have been fabricated functioning in the dc mode up to 200 °C. The largest advance, concerning development of devices for RF application, has been done in fabrication of different types of FETs. For FETs with gate length 0.2 μm frequencies fT = 24.6 GHz, fmax(MAG) = 63 GHz and fmax(U) = 80 GHz were reported. Further, capacitors and switches, working up to 450 °C and 650 °C, respectively, have also been fabricated. Low resistant thermostable resistors have been investigated up to 800 °C. Temperature dependence of field emission from diamond films has been measured up to 950 °C. However, the diamond based electronics is still regarded to be in its infancy. The prerequisite for a successful application of diamond for the fabrication of electronic devices is availability of wafer diamond, i.e. large area, high quality, inexpensive, diamond single crystal substrates. A step forward in this direction has been made recently. Diamond films grown on multilayer substrate Ir/YSZ/Si(001) having qualities close those of homoepitaxial diamond have been reported recently. © Springer Science + Business Media, Inc. 2006.
|
|
