| 1. |
- Krishnaraja, Abinaya, et al.
(författare)
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Tuning of Source Material for InAs/InGaAsSb/GaSb Application-Specific Vertical Nanowire Tunnel FETs
- 2020
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Ingår i: ACS Applied Electronic Materials. - : American Chemical Society (ACS). - 2637-6113. ; 2:9, s. 2882-2887
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Tidskriftsartikel (refereegranskat)abstract
- Tunnel field-effect transistors (TFETs) are promising candidates that have demonstrated potential for and beyond the 3 nm technology node. One major challenge for the TFETs is to optimize the heterojunction for high drive currents while achieving steep switching. Thus far, such optimization has mainly been addressed theoretically. Here, we experimentally investigate the influence of the source segment composition on the performance for vertical nanowire InAs/InGaAsSb/GaSb TFETs. Compositional analysis using transmission electron microscopy is combined with simulations to interpret the results from electrical characterization data. The results show that subthreshold swing (S) and transconductance (gm) decrease with increasing arsenic composition until the strain due to lattice mismatch increases them both. The role of indium concentration at the junction is also examined. This systematic optimization has rendered sub-40 mV/dec operating TFETs with a record transconductance efficiency gm/ID = 100 V-1, and it shows that different source materials are preferred for various applications.
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| 2. |
- Kilpi, Olli Pekka, et al.
(författare)
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High-Performance Vertical III-V Nanowire MOSFETs on Si with gm> 3 mS/μm
- 2020
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Ingår i: IEEE Electron Device Letters. - 0741-3106. ; 41:8, s. 1161-1164
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Tidskriftsartikel (refereegranskat)abstract
- Vertical III-V nanowire MOSFETs have demonstrated excellent performance including high transconductance and high Ion. One main bottleneck for the vertical MOSFETs is the large access resistance arising from the contacts and ungated regions. We demonstrate a process to reduce the access resistance by combining a gate-last process with ALD gate-metal deposition. The devices demonstrate fully scalable gm down to Lg = 25 nm. These vertical core/shell InAs/InGaAs MOSFETs demonstrate gm = 3.1 mS/μm and Ron = 190 Ωμm. This is the highest gm demonstrated on Si. Transmission line measurement verifies a low contact resistance with RC = 115 Ωμm, demonstrating that most of the MOSFET access resistance is located in the contact regions.
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| 3. |
- Persson, Anton E.O., et al.
(författare)
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Reduced annealing temperature for ferroelectric HZO on InAs with enhanced polarization
- 2020
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 116:6
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Tidskriftsartikel (refereegranskat)abstract
- Deposition, annealing, and integration of ferroelectric Hf x Zr 1 - x O 2 (HZO) thin films on the high-mobility semiconductor InAs using atomic layer deposition are investigated. Electrical characterization reveals that the HZO films on InAs exhibit an enhanced remanent polarization compared to films formed on a reference TiN substrate, exceeding 20 μ C / cm 2 even down to an annealing temperature of 370 °C. For device applications, the thermal processes required to form the ferroelectric HZO phase must not degrade the high-κ/InAs interface. We find by evaluation of the capacitance-voltage characteristics that the electrical properties of the high-κ/InAs are not significantly degraded by the annealing process, and high-resolution transmission electron microscopy verifies a maintained sharp high-κ/InAs interface.
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| 4. |
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| 5. |
- Abramovich, Shoshana, et al.
(författare)
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Some new Hermite-Hadamard and Fejer type inequalities without convexity/concavity
- 2020
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Ingår i: Mathematical Inequalities & Applications. - : Element. - 1331-4343 .- 1848-9966. ; 23:2, s. 447-458
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we discuss the Hermite-Hadamard and Fejer inequalities vis-a-vis the convexity concept. In particular, we derive some new theorems and examples where Hermite-Hadamard and Fejer type inequalities are satisfied without the assumptions of convexity or concavity on the actual interval [a,b]
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| 6. |
- Akishev, Gabdolla, et al.
(författare)
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Inequalities for the Fourier coefficients in unbounded orthogonal systems in generalized Lorentz spaces
- 2020
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Ingår i: Nonlinear Studies. - : Cambridge Scientific Publishers Ltd. - 1359-8678. ; 27:4, s. 1137-1155
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Tidskriftsartikel (refereegranskat)abstract
- This paper is an essential complement of the research recently presented in [1], [2]. A number of classical Fourier inequalities related to Fourier coefficients with respect to unbounded orthogonal systems are generalized and complemented. All results are given in the case of generalized Lorentz spaces.
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| 7. |
- Akishev, G., et al.
(författare)
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Some new Fourier inequalities for unbounded orthogonal systems in Lorentz–Zygmund spaces
- 2020
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Ingår i: Journal of inequalities and applications. - : Springer. - 1025-5834 .- 1029-242X. ; , s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we prove some essential complements of the paper (J. Inequal. Appl.2019:171, 2019) on the same theme. We prove some new Fourier inequalities in thecase of the Lorentz–Zygmund function spaces Lq,r(log L)α involved and in the casewith an unbounded orthonormal system. More exactly, in this paper we prove anddiscuss some new Fourier inequalities of this type for the limit case L2,r(log L)α, whichcould not be proved with the techniques used in the paper (J. Inequal. Appl.2019:171, 2019).
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| 8. |
- Høibakk, Ralph, et al.
(författare)
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A New Look at the Single Ladder Problem (SLP) via Integer Parametric Solutions to the Corresponding Quartic Equation
- 2020
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Ingår i: Mathematics. - : MDPI. - 2227-7390. ; 8:2, s. 1-21
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Tidskriftsartikel (refereegranskat)abstract
- The aim is to put new light on the single ladder problem (SLP). Some new methods for finding complete integer solutions to the corresponding quartic equation z(4) - 2Lz(3) + ( L-2 - a(2) - b(2))z(2) + 2La(2)z - L(2)a(2) = 0 are developed. For the case L >= L-min, these methods imply a complete parametric representation for integer solutions of SLP in the first quadrant. Some corresponding (less complete) results for the case L > L-min are also pointed out.
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| 9. |
- Lukkassen, D., et al.
(författare)
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Some inequalities related to strongconvergence of Riesz logarithmic means
- 2020
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Ingår i: Journal of inequalities and applications. - : Springer. - 1025-5834 .- 1029-242X. ; , s. 1-17
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we derive a new strong convergence theorem of Riesz logarithmicmeans of the one-dimensional Vilenkin–Fourier (Walsh–Fourier) series. Thecorresponding inequality is pointed out and it is also proved that the inequality is in asense sharp, at least for the case with Walsh–Fourier series.
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| 10. |
- Maliakkal, Carina B., et al.
(författare)
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Independent Control of Nucleation and Layer Growth in Nanowires
- 2020
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 14:4, s. 3868-3875
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Tidskriftsartikel (refereegranskat)abstract
- Control of the crystallization process is central to developing nanomaterials with atomic precision to meet the demands of electronic and quantum technology applications. Semiconductor nanowires grown by the vapor-liquid-solid process are a promising material system in which the ability to form components with structure and composition not achievable in bulk is well-established. Here, we use in situ TEM imaging of Au-catalyzed GaAs nanowire growth to understand the processes by which the growth dynamics are connected to the experimental parameters. We find that two sequential steps in the crystallization process - nucleation and layer growth - can occur on similar time scales and can be controlled independently using different growth parameters. Importantly, the layer growth process contributes significantly to the growth time for all conditions and will play a major role in determining material properties such as compositional uniformity, dopant density, and impurity incorporation. The results are understood through theoretical simulations correlating the growth dynamics, liquid droplet, and experimental parameters. The key insights discussed here are not restricted to Au-catalyzed GaAs nanowire growth but can be extended to most compound nanowire growths in which the different growth species has very different solubility in the catalyst particle.
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