| 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. |
- Egard, Mikael, et al.
(författare)
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High-Frequency Performance of Self-Aligned Gate-Last Surface Channel In0.53Ga0.47As MOSFET
- 2012
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Ingår i: IEEE Electron Device Letters. - 0741-3106. ; 33:3, s. 369-371
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a self-aligned L-g = 55 nm In-0.53 Ga-0.47 As MOSFET incorporating metal-organic chemical vapor deposition regrown n(++) In0.6Ga0.4As source and drain regions, which enables a record low on-resistance of 199 Omega mu m. The regrowth process includes an InP support layer, which is later removed selectively to the n(++) contact layer. This process forms a high-frequency compatible device using a low-complexity fabrication scheme. We report on high-frequency measurements showing f(max) of 292 GHz and f(t) of 244 GHz. These results are accompanied by modeling of the device, which accounts for the frequency response of gate oxide border traps and impact ionization phenomenon found in narrow band gap FETs. The device also shows a high drive current of 2.0 mA/mu m and a high extrinsic transconductance of 1.9 mS/mu m. These excellent properties are attributed to the use of a gate-last process, which does not include high temperature or dry-etch processes.
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| 3. |
- Lind, Erik, et al.
(författare)
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Improved subthreshold slope in an InAs nanowire heterostructure field-effect transistor
- 2006
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 6:9, s. 1842-1846
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Tidskriftsartikel (refereegranskat)abstract
- An n-type InAs/InAsP heterostructure nanowire field-effect transistor has been fabricated and compared with a homogeneous InAs field-effect transistor. For the same device geometry, by introduction of the heterostructure, the threshold voltage is shifted 4 V, the maximum current on-off ratio is enhanced by a factor of 10 000, and the subthreshold swing is lowered by a factor 4 compared to the homogeneous transistor. At the same time, the drive current remains constant for a fixed gate overdrive. A single nanowire heterostructure transistor has a transconductance of 5 mu A/V at a low source-drain voltage of 0.3 V. For the homogeneous InAs transistor, we deduced a high electron mobility of 1500 cm(2)/Vs.
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| 4. |
- Andersson, Anton, et al.
(författare)
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Design of a Foiling Optimist
- 2018
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Ingår i: Journal of Sailboat Technology. ; 2018, s. 1-24
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Tidskriftsartikel (refereegranskat)abstract
- Because of the successful application of hydrofoils on the America's Cup catamarans in the past two campaigns the interest in foiling sailing craft has boosted. Foils have been fitted to a large number of yachts with great success, ranging from dinghies to ocean racers. An interesting question is whether one of the slowest racing boats in the world, the Optimist dinghy, can foil, and if so, at what minimum wind speed. The present paper presents a comprehensive design campaign to answer the two questions. The campaign includes a newly developed Velocity Prediction Program (VPP) for foiling/non-foiling conditions, a wind tunnel test of sail aerodynamics, a towing tank test of hull hydrodynamics and a large number of numerical predictions of foil characteristics. An optimum foil configuration is developed and towing tank tested with satisfactory results. The final proof of the concept is a successful on the water test with stable foiling at a speed of 12 knots.
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| 5. |
- Frisk, Karin, et al.
(författare)
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Characterisation of EBM-built shelled samples of Ti6Al4V compacted by HIP
- 2016
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Ingår i: World PM 2016 Congress and Exhibition. - : European Powder Metallurgy Association (EPMA). - 9781899072484
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Konferensbidrag (refereegranskat)abstract
- Compaction of additively manufactured Ti6Al4V components by Hot Isostatic Pressing (HIP) is often applied to eliminate porosity, producing fully dense material. In the present work shelled samples produced by Electron Beam Melting with the Arcam process (EBM) were compacted by HIP to produce fully dense samples. Cylindrical samples were studied. The walls of the cylinders were built with EBM, and the powder from the process was left uncompacted inside the cylinders. Samples with different wall thicknesses were produced. The samples were thereafter subjected to a HIP compaction. The critical wall thicknesses needed for compaction were evaluated, and the microstructures characterized. The results show that fully dense samples, with very fine microstructures, are possible.
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| 6. |
- 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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| 7. |
- Kilpi, Olli Pekka, et al.
(författare)
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Vertical InAs/InGaAs Heterostructure Metal-Oxide-Semiconductor Field-Effect Transistors on Si
- 2017
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 17:10, s. 6006-6010
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Tidskriftsartikel (refereegranskat)abstract
- III-V compound semiconductors offer a path to continue Moore's law due to their excellent electron transport properties. One major challenge, integrating III-V's on Si, can be addressed by using vapor-liquid-solid grown vertical nanowires. InAs is an attractive material due to its superior mobility, although InAs metal-oxide-semiconductor field-effect transistors (MOSFETs) typically suffer from band-to-band tunneling caused by its narrow band gap, which increases the off-current and therefore the power consumption. In this work, we present vertical heterostructure InAs/InGaAs nanowire MOSFETs with low off-currents provided by the wider band gap material on the drain side suppressing band-to-band tunneling. We demonstrate vertical III-V MOSFETs achieving off-current below 1 nA/μm while still maintaining on-performance comparable to InAs MOSFETs; therefore, this approach opens a path to address not only high-performance applications but also Internet-of-Things applications that require low off-state current levels.
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| 8. |
- Berg, Martin, et al.
(författare)
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Electrical Characterization and Modeling of Gate-Last Vertical InAs Nanowire MOSFETs on Si
- 2016
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Ingår i: IEEE Electron Device Letters. - 0741-3106. ; 37:8, s. 966-969
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Tidskriftsartikel (refereegranskat)abstract
- Vertical InAs nanowire transistors are fabricated on Si using a gate-last method, allowing for lithography-based control of the vertical gate length. The best devices combine good ON- and OFF-performance, exhibiting an ON-current of 0.14 mA/μm, and a sub-threshold swing of 90 mV/dec at 190 nm LG. The device with the highest transconductance shows a peak value of 1.6 mS/μm. From RF measurements, the border trap densities are calculated and compared between devices fabricated using the gate-last and gate-first approaches, demonstrating no significant difference in trap densities. The results thus confirm the usefulness of implementing digital etching in thinning down the channel dimensions.
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| 9. |
- Berg, Martin, et al.
(författare)
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Self-aligned, gate-last process for vertical InAs nanowire MOSFETs on Si
- 2016
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Ingår i: Technical Digest - International Electron Devices Meeting, IEDM. - 9781467398930 ; 2016-February
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Konferensbidrag (refereegranskat)abstract
- In this work, we present a novel self-aligned gate-last fabrication process for vertical nanowire metal-oxide-semiconductor field-effect transistors. The fabrication method allows for exposure dose-defined gate lengths and a local diameter reduction of the intrinsic channel segment, while maintaining thicker highly doped access regions. Using this process, InAs nanowire transistors combining good on-and off-performance are fabricated demonstrating Q = gm,max/SS = 8.2, which is higher than any previously reported vertical nanowire MOSFET.
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| 10. |
- Berg, Martin, et al.
(författare)
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Single Balanced Down-Conversion Mixer Utilizing Indium Arsenide Nanowire MOSFETs
- 2014
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Ingår i: 26th International Conference on Indium Phosphideand Related Materials (IPRM). - 1092-8669.
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Konferensbidrag (refereegranskat)abstract
- We have fabricated single balanced down-conversion mixer circuits using InAs nanowire MOSFETs as both active and passive devices. This is achieved by a combination of electron beam lithography and UV-lithography with a line width of 12 mu m. The circuits exhibit a low frequency voltage conversion gain of 6 dB, a -3 dB cutoff frequency of 2 GHz and a power consumption of 3.8 mW, while operating at a supply voltage of 1.5 V. The circuits retain circuit functionality even for a supply voltage of 1 V.
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