| 11. |
- Bengtsson, Stefan, 1961, et al.
(författare)
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IC process compatible preparation of silicon interfaces using the silicon-to-silicon direct bonding method
- 1989
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Ingår i: ESSDERC '89. 19th European Solid State Devices Research Conference. ; , s. 353-
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Konferensbidrag (refereegranskat)abstract
- Silicon/silicon interfaces were prepared by wafer bonding using the silicon-to-silicon direct bonding method. Silicon/silicon interfaces (n/n-type) with excellent electric properties were prepared, by using hydrophobic wafer surfaces, at temperatures in the range of 700°C to 1000°C. The influence of the bonded interface on device characteristics of bonded p+n junctions prepared at low temperatures was seen as n-factors larger than 2 at forward bias. A correlation between n-factors and the density of states in the bandgap was found. In hydrophilic samples, the density of voids at the bonded interface was determined mainly in the contacting of the wafer surfaces at room temperature. Compared to hydrophilic samples, hydrophobic samples were held together at a smaller fraction of the area before heat treatment. After the heat treatments, no difference in the density of voids was found
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| 12. |
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| 13. |
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| 14. |
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| 15. |
- Bengtsson, Stefan, 1961, et al.
(författare)
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Oxide degradation of wafer bonded MOS capacitors following Fowler-Nordheim electron injection
- 1992
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Ingår i: Proceedings of the First International Symposium on Semiconductor Wafer Bonding: Science, Technology and Applications. ; , s. 339-
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Konferensbidrag (refereegranskat)abstract
- The degradation of wafer bonded silicon dioxides as a result of Fowler-Nordheim electron injection has been studied. The samples were MOS capacitors with wafer bonded SiO2-SiO2 interfaces at the oxide center. The charge trapping in the oxide and the Si-SiO2 interface state generation were monitored as a function of injected charge and compared to reference MOS capacitors without bonded interfaces. A larger change in the oxide charge was found in the bonded capacitors as compared to the reference structures. The centroid of trapped negative oxide charge was found to be located close to the SiO2-SiO2 interface in the bonded structures, while the reference structures exhibited centroids close to the injecting contact. The electron injection caused approximately the same generation of interface states in both groups of capacitors
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| 16. |
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| 17. |
- Bonmann, Marlene, 1988, et al.
(författare)
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Effect of oxide traps on channel transport characteristics in graphene field effect transistors
- 2017
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Ingår i: Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures. - : American Vacuum Society. - 2166-2754 .- 2166-2746. ; 35:1, s. 01A115-
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Tidskriftsartikel (refereegranskat)abstract
- A semiempirical model describing the influence of interface states on characteristics of gatecapacitance and drain resistance versus gate voltage of top gated graphene field effect transistors ispresented. By fitting our model to measurements of capacitance–voltage characteristics and relatingthe applied gate voltage to the Fermi level position, the interface state density is found. Knowing theinterface state density allows us to fit our model to measured drain resistance–gate voltagecharacteristics. The extracted values of mobility and residual charge carrier concentration arecompared with corresponding results from a commonly accepted model which neglects the effect ofinterface states. The authors show that mobility and residual charge carrier concentration differsignificantly, if interface states are neglected. Furthermore, our approach allows us to investigate indetail how uncertainties in material parameters like the Fermi velocity and contact resistanceinfluence the extracted values of interface state density, mobility, and residual charge carrierconcentration.
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| 18. |
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| 19. |
- Ducroquet, F., et al.
(författare)
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Admittance spectroscopy of Si/LaLuO3 and Si/GdSiO MOS Structures (Invited)
- 2012
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Ingår i: ECS Transactions. - : The Electrochemical Society. - 1938-5862 .- 1938-6737. ; 45:3, s. 103 - 117
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Konferensbidrag (refereegranskat)abstract
- Interface states at the gate oxide/channel of metal oxide semiconductor (MOS) transistors generally result in detrimental effects on the device performance which need to be considered for the new generations of high-k dielectrics. In this paper, the admittance of Gadolinium silicate (GdSiO) and Lanthanum Lutetium oxide (LaLuO3) MOS capacitors were investigated as a function of the signal frequency, temperature and gate voltage. The Arrhenius plots of the peak pulsations extracted from the conductance spectra have been discussed on the bases of simulated data taking into account a distribution of the trap energy levels and a thermally enhanced capture cross-section. The consequences of a peaked interface state distribution on the evolution of activation energies are shown to lead to Arrhenius plots following the Meyer-Neldel Rule.
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| 20. |
- Engström, Lil, 1943-
(författare)
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Möjligheter till lärande i matematik : Lärares problemformuleringar och dynamisk programvara
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis presents the first Swedish empirical evidence on how teachers employ a dynamic mathematical software when teaching mathematics in upper secondary school. The study examines: a) How teachers formulate mathematical problems? b) How they use the experience the students have gained? and c) What use they make of the software’s potential? These questions are examined through classroom observations followed up by discussions with the teachers.The study comprises three teachers and shows that they have very different mathematical experiences and teaching skills. A questionnaire was sent to the teachers prior to the classroom visits to collect relevant background information; e.g., the teachers were asked to describe their teacher training, their view of mathematics and of how a dynamic software could contribute to their teaching.The results show that the teachers’ ability to pose thought-provoking openended problems is the most important factor as it significantly influences what the students learn. The way a mathematical problem is formulated could, in conjunction with a dynamic software, actually limit the students’ achievement.However, this study confirms that it could also provide an opportunity for students to discover new mathematical relations, draw conclusions, generalise and formulate hypotheses. This could in turn lead to an in formally proving a mathematical relation. A conclusion of the study is that to be successful, teachers need a good mathematical background with a firm knowledge base and an understanding of the software’s potential, but they also need the skill to formulate open-ended problems that will enable their students to work successfully with a dynamic mathematical software.
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