| 1. |
- Cheng, Jie, et al.
(författare)
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Preparation of Surface Modified Ceria Nanoparticles as Abrasives for the Application of Chemical Mechanical Polishing (CMP)
- 2020
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Ingår i: ECS Journal of Solid State Science and Technology. - : ELECTROCHEMICAL SOC INC. - 2162-8769 .- 2162-8777. ; 9:2
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a method to improve the chemical mechanical polishing (CMP) performance of ceria as abrasive particles was proposed. Surface doping of ceria nanoparticles was realized by incipient impregnation method, in order to improve its valance change properties (Ce3+/Ce4+). This study presents detailed characterization of the lanthanide-doped CeO2 by both experimental methods and density functional theory (DFT) calculation. The dispersion stability of the doped ceria nanoparticles in CMP slurries are investigated. Results show that the doped CeO2 nanoparticles exhibit more oxygen vacancies and higher content of Ce3+ compared with the pristine CeO2. Good dispersion stability of the doped CeO2 nanoparticles could be achieved by adding dispersants in the CMP slurries.
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| 2. |
- Pedersen, Henrik, et al.
(författare)
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Perspective-Current Understanding of the Halogenated Deposition Chemistry for Chemical Vapor Deposition of SiC
- 2020
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Ingår i: ECS Journal of Solid State Science and Technology. - : ELECTROCHEMICAL SOC INC. - 2162-8769 .- 2162-8777. ; 9:10
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The deposition rate of silicon carbide (SiC) in chemical vapor deposition (CVD) can be boosted by addition of chlorine. This has been explored and applied for hard coatings and electronic grade SiC. We briefly summarize the recent research done in the field of SiC CVD and discuss the understanding of the CVD chemistry with addition of halides. We seek to improve a previous statement that SiCl(2)is the main silicon species for growth of SiC. Recent experiments and modeling suggest that SiCl2, and its fluorinated and brominated analogues, are inactive and that SiF/SiCl/SiBr are the main halogenated species for growth.
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| 3. |
- Yin, X., et al.
(författare)
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Study of Isotropic and Si-Selective Quasi Atomic Layer Etching of Si1-xGex
- 2020
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Ingår i: ECS Journal of Solid State Science and Technology. - : Institute of Physics Publishing. - 2162-8769 .- 2162-8777. ; 9:3
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Tidskriftsartikel (refereegranskat)abstract
- The lateral and vertical gate-all-around (GAA) field-effect transistors are considered the most promising candidates for next generation logic device at and beyond 3-nm technology node. SiGe plays an important role in these devices as the sacrificial layer or channel material and needs isotropic etching. In this paper, an advanced etching process termed quasi atomic layer etching (qALE) is developed with advantages of controllable etch rate and atomically smooth surfaces. The qALE of SiGe is based on wet chemical etching, in which H2O2 is applied to oxidate the surface with cyclic manner, and diluted buffered oxide etchant (dBOE) is applied to remove the oxide. The profiles of SiGe qALE for quasi-self-limited behavior, etch rate and the effect in concentration and temperature of H2O2 have been studied. The etch per cycle (EPC) of Si0.7Ge0.3 is 0.50 nm and the etching selectivity between Si0.7Ge0.3 and heavily p-type doped silicon is 4.99 in Si/SiGe/Si stacked layers with (110) sidewall. The etch rate and the selectivity are influenced by Ge fraction of SiGe and the boron doping in Si. The root mean square (RMS) roughness after 60 cycles qALE is 0.183 nm indicating atomically smooth surfaces. Finally, the application of qALE for vertical nanowire compared with wet continuous etching is discussed in this work. © 2020 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.
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| 4. |
- Zurauskaite, Laura, et al.
(författare)
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Process Conditions for Low Interface State Density in Si-passivated Ge Devices with TmSiO Interfacial Layer
- 2020
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Ingår i: ECS Journal of Solid State Science and Technology. - : The Electrochemical Society. - 2162-8769 .- 2162-8777. ; 9:12
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Tidskriftsartikel (refereegranskat)abstract
- In this work we study the epitaxial Si growth with Si2H6 for Ge surface passivation in CMOS devices. The Si-caps are grown on Ge in the hydrogen desorption limited regime at a nominal temperature of 400 degrees C. We evaluate the process window for the interface state density and show that there is an optimal Si-cap thickness between 8 and 9 monolayers for D-it < 510(11) cm(-2) eV(-1). Moreover, we discuss the strong impact of the Si-cap growth time and temperature on the interface state density, which arises from the Si thickness dependence on these growth parameters. Furthermore, we successfully transfer a TmSiO/Tm2O3/HfO2 gate stack process from Si to Ge devices with optimized Si-cap, yielding interface state density of 310(11) eV(-1) cm(-2) and a significant improvement in oxide trap density compared to GeOx passivation.
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| 5. |
- Sharma, Suchinder, 1982, et al.
(författare)
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Photoluminescence Properties and Fabrication of Red-Emitting LEDs based on Ca9Eu(VO4)(7) Phosphor
- 2020
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Ingår i: ECS Journal of Solid State Science and Technology. - 2162-8777 .- 2162-8769. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- We study the photoluminescence properties of the red-emitting phosphor Ca9Eu(VO4)(7) and establish a strong red emission centered at 613 nm under excitation at 395 nm (near ultra violet light, near-UV light) due to the intra-configurational D-5(0) -> F-7(2) transition within the 4f(6) configuration of the Eu3+ ions. The intensity of the emitted light decreases with increasing temperature and at T = 470 K about 50% of the intensity of the emitted light at room temperature is lost. Five different red-LED prototypes were constructed by applying a mixture of Ca9Eu(VO4)(7) phosphor and silicone gel on the headers of near-UV LED chips. The prototypes showed a color output from violet for the lowest phosphor concentration (133 g phosphor /l silicone gel), reaching an almost pure red-light output for the highest phosphor concentration (670 g phosphor /l silicone gel). The luminous efficiency of optical radiation (LER) was found to decrease slightly with increasing applied current. For the highest phosphor concentration, the LER decreases from 238 lmW(-1) for 1 mA current supply to 235 lmW(-1) for 18 mA current supply. The external quantum efficiency decreased from 7.33% for the lowest phosphor containing LED prototype to 4.13% for the highest one. (C) The Author(s) 2019. Published by ECS.
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