| 1. |
- Fobelets, Kristel, et al.
(författare)
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High-frequency capacitance of bipolar resonant tunneling diodes
- 1996
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 79:2, s. 905-910
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Tidskriftsartikel (refereegranskat)abstract
- The high-frequency characteristics of bipolar resonant tunneling diodes are experimentally investigated at room temperature. The electron accumulation and discharging in these resonant tunneling light-emitting diodes are studied at frequencies up to 35 GHz. The experiments show capacitance peaks due to electron charge disappearing from the quantum well. The measurements are found to be in agreement with our theoretical model for the calculation of the high-frequency characteristics of resonant tunneling devices. The high-frequency characteristics of the bipolar light-emitting resonant tunneling diode are compared to the unipolar resonant tunneling diode and the resonant interband tunneling diode. The comparison shows a similar discharging characteristic of the quantum well, but a different overall variation of the capacitance.
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| 2. |
- Dillner, Lars, 1968, et al.
(författare)
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Analysis of Symmetric Varactor Frequency Multipliers
- 1997
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Ingår i: Microwave and Optical Technology Letters. ; 15:1, s. 26-29
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Tidskriftsartikel (refereegranskat)abstract
- We investigate efficiency limitations of frequency multipliers with the use of a simple model for symmetric varactors. Our calculations show that the conversion efficiency is improved for a C(V) shape with large nonlinearity at zero volt bias. For quintuplers, the optimal embedding impedance at the third harmonic is an inductance in resonance with the varactor diode capacitance.
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| 3. |
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| 4. |
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| 5. |
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| 6. |
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| 7. |
- Fu, Ying, 1964, et al.
(författare)
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AlGaAs/GaAs and InAlAs/InGaAs Heterostructure Barrier Varactors
- 1997
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 82:11, s. 5568-5572
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Tidskriftsartikel (refereegranskat)abstract
- By the Schrödinger and Poisson equations, we have theoretically investigated AlGaAs/GaAs and InAlAs/InGaAs single barrier varactors. The energy band structure, carrier distribution, and conduction current are fully exploited for varactor design. We have explained the experimental current-voltage and capacitance-voltage measurements very well. A simple analytical model for energy band structure is derived based on the Schrödinger and Poisson equation calculation. It is found that a barrier structure of 3 nm Al0.3Ga0.7As/3 nm AlAs/3nm Al0.3Ga0.7As for an Al0.3Ga0.7As/GaAs varactor and a barrier structure of 8 nm In0.52Al0.48As/3 nm AlAs/8 nm In0.52Al0.48As for In0.52Al0.48As/In0.47GaAs are optimal for minimal conduction currents.
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| 8. |
- Fu, Ying, 1964, et al.
(författare)
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Capacitance Analysis for AlGaAs/GaAs and InAlAs/InGaAs Heterostructure Barrier Varactor Diodes
- 1998
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 83:3, s. 1457-1462
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Tidskriftsartikel (refereegranskat)abstract
- By self-consistently solving Schro¨dinger and Poissons equations, we have investigated the capacitances of AlGaAs/GaAs and InAlAs/InGaAs heterostructure barrier varactors. When compared with semiclassical particle model, quantum mechanics show that the maximal capacitance of the varactor is saturated when the spacer and barrier are thin. When the spacer and barrier are very thick, both the quantum mechanics and semiconductor particle approach result in the same conclusion, namely, the maximal capacitance is inversely proportional to the sum of the spacer and barrier thicknesses. We have also shown that the maximal capacitance increases for high carrier effective mass.
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| 9. |
- Hollung, Stein, 1970, et al.
(författare)
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A 141-GHz Integrated Quasi-Optical Slot Antenna Tripler
- 1999
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Ingår i: IEEE Antennas and Propagation Society International Symposium. - 078035639X ; 4, s. 2394-2397
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Konferensbidrag (refereegranskat)abstract
- We present a quasi-optical frequency tripler with heterostructure barrier varactor (HBV) diodes soldered across two slot antennas and located at the focal plane of a dielectric lens. The slot antennas are fed from a WR-22 waveguide connected to a Gunn oscillator. A quasi-optical high-pass filter is used to tune the slot impedance and increase the conversion efficiency. The symmetric capacitance-voltage and asymmetric current-voltage characteristics of the HBV diodes only allows odd harmonics of the applied signal to be generated, and thus simplifies the frequency tripler design.
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| 10. |
- Hollung, Stein, 1970, et al.
(författare)
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A 141-GHz Quasi-Optical HBV Diode Frequency Tripler
- 1999
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Ingår i: Tenth International Symposium on Space Terahertz Technology. ; , s. 492-500
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Konferensbidrag (refereegranskat)abstract
- A 141-GHz quasi-optical heterostructure barrier varactor (HBV) diode frequency tripler is presented. The tripler consists of two slot antennas loaded with FEW diodes and located at the focal plane of a dielectric lens. A quasi-optical high-pass filter is used at the output to improve the conversion efficiency and act as a tuning element for the slot antennas. The tripler demonstrates an effectively isotropic radiated power (EIRP) of 2.24 W at 141 GHz with an input power of 143 mW. The corresponding radiated power is 11.5 mW and the tripler conversion efficiency is about 8%.
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| 11. |
- Kollberg, Erik, 1937, et al.
(författare)
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Heterostructure Barrier Varactor Multipliers
- 1998
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Ingår i: 2nd ESA Workshop on Millimetre Wave Technology and Applications. ; , s. 429-434
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Konferensbidrag (refereegranskat)abstract
- We describe the Heterostructure Barrier Varactor (HBV) diode and its application in frequency multipliers. Different varactor models are presented that easily can be used in large signal simulations. Results from frequency multiplier measurements are presented. The delivered maximum output power at 234 GHz is 3.6 mW. Simulations show that the output power is limited by excessive conduction current due to increased diode temperature.
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| 12. |
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| 13. |
- Mahiey, S, et al.
(författare)
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A Broadband Frequency Tripler for SIS Receivers
- 1998
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Ingår i: Ninth International Symposium on Space Terahertz Technology. ; , s. 481-491
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Konferensbidrag (refereegranskat)abstract
- Considerable success has recently been gained in the design and production of high powered frequency triplers incorporating Schottky varactor diodes. The design approach that was used for this goal has now been turned to the design of fixed tuned, broadband frequency triplers specifically intented for use in SIS receivers.The tripler reported here makes the use of a Heterostructure Barrier Varactor or HBV. A waveguide circuit has been designed that provides more than 50µW of output power for an input power of 10mW over a frequency range of 250 - 300GHz completely fixed tuned and without the need for bias.Further modification of the waveguide circuit should extend the useful fixed tuned bandwidth to greater than 100GHz centered at 300GHz.
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| 14. |
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| 15. |
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| 16. |
- Stake, Jan, 1971, et al.
(författare)
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Analysis of Carrier Transport in a Heterostructure Barrier Varactor Diode Tripler
- 1997
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Ingår i: International Semiconductor Device Research Symposium (ISDRS). ; , s. 183-186
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Konferensbidrag (refereegranskat)abstract
- We report the time evolution and the spatial variation of the conduction band, the electric field, and the carrier density for a GaAs/Al0.7GaAs Heterostructure Barrier Varactor diode operating in a 3x90 GHz frequency tripler. The third harmonic output power and optimal embedding impedances are given for two different diodes at pump powers of 50 mW and 100 mW.
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| 17. |
- Stake, Jan, 1971, et al.
(författare)
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Design of 100-900 GHz AlGaAs/GaAs Planar Heterostructure Barrier Varactor Frequency Triplers
- 1998
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Ingår i: Ninth International Symposium on Space Terahertz Technology. ; , s. 359-366
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Konferensbidrag (refereegranskat)abstract
- In this paper we offer a simple set of accurate frequency-domain design equations that can be used to calculate optimal embedding impedances and tripling efficiency. These equations can be used for a wide range of device and circuit parameters. The effects of parasitic resistance and operating temperature on device performance, and how these parameters vary with device design are explored. Comparisons to experiment are made for planar HBVs demonstrating at least 3 % efficiency at 78 GHz input frequency and 50 mW of input power.
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| 18. |
- Stake, Jan, 1971, et al.
(författare)
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Effects of Self-Heating on Planar Heterostructure Barrier Varactor Diodes
- 1998
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Ingår i: IEEE Transactions on Electron Devices. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9383. ; 45:11, s. 2298-2303
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Tidskriftsartikel (refereegranskat)abstract
- The conversion efficiency for planar Al0.7GaAs-GaAs heterostructure barrier varactor triplers is shown to be reduced from a theoretical efficiency of 10% to 3% due to self-heating. The reduction is in accordance with measurements on planar Al0.7GaAs-GaAs heterostructure barrier varactor (HBV) triplers to 261 GHz at room temperature and with low temperature tripler measurements to 255 GHz. The delivered maximum output power at 261 GHz is 2.0 mW. Future HBV designs should carefully consider and reduce the device thermal resistance and parasitic series resistance. Optimization of the RF circuit for a 10 ?m diameter device yielded a delivered output power of 3.6 mW (2.5% conversion efficiency) at 234 GHz
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| 19. |
- Stake, Jan, 1971, et al.
(författare)
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Fabrication and Characterisation of Heterostructure Barrier Varactor Diodes
- 1996
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report deals with fabrication and characterisation of Heterostructure Barrier Varactor (HBV) diodes for frequency multiplier applications. The process steps involved are clean-ing, device isolation, passivation, ohmic contacts, thick metal, air-bridge formation, transfer of EPI-layers to copper substrate, and formation of mechanical support for the whisker. These fabrication steps are described in detail.The characterisation techniques of HBVs are described in detail. An equivalent circuit is extracted from on-wafer S-parameter measurements (0,045-50 GHz). In combination with DC-measurements (ohmic contact resistance, I-V characteristic) a large-signal model for frequencies up to the submillimetre wavelength can be extracted. Furthermore, the relative error in extracted varactor parameters from high frequency S-parameter measurements is presented.The results of lattice matched and pseudomorphic GaAs/AlGaAs, InGaAs/InAlAs, InAs/AlSb and phosphide containing materials for HBVs are presented. The best material for millimetre and submillimetre wave HBVs, among those tested, is the In0,53Ga0,47As/In0,52Al0,48As system with a thin AlAs layer (30 Å) in the middle of the barrier.
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| 20. |
- Stake, Jan, 1971
(författare)
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Heterostructure Barrier Varactor Diodes for Frequency Multiplier Applications
- 1996
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with fabrication, characterisation and modelling of the Heterostructure Barrier Varactor (HBV) diode and its use in frequency multiplier circuits. Different aspects of material structures and frequency multipliers are described. The aim of the work presented is to develop processes to fabricate state of the art HBVs and multipliers in the millimetre and submillimetre wave region.Different III-V material systems for HBVs have been tested. The results of lattice matched and pseudomorphic GaAs/AlGaAs, InGaAs/InAlAs, InAs/AlSb and phosphide containing materials for HBVs are presented. The state of the art material for millimetre and submillimetre wave HBVs is the In0,53GaAs/In0,52AlAs system with a thin AlAs layer (30 Å) in the middle of the barrier.Both simple analytical models and a self-consistent Poisson/Schrödinger approach are used to predict and optimise HBV diodes. The HBVs were evaluated using on-wafer high frequency S-parameter measurements. Finally, an HBV design procedure based on analytical models is proposed.
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| 21. |
- Stake, Jan, 1971, et al.
(författare)
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Improved Diode Geometry for Planar Heterostructure Barrier Varactors
- 1999
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Ingår i: Tenth International Symposium on Space Terahertz Technology. ; , s. 485-491
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Konferensbidrag (refereegranskat)abstract
- We report state-of-the-art performance of tripler efficiency and output power for a new design of AlGaAs-based heterostructure barrier varactor diodes. The new diodes were designed for reduced thermal resistance and series resistance. An efficiency of 4.8% and a maximum output power of 4 mW was achieved at an output frequency of 246 GHz.
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| 22. |
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| 23. |
- Stake, Jan, 1971
(författare)
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Planar Heterostructure Barrier Varactor Diodes for Millimetre Wave Applications
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with fabrication, characterisation and modelling of the Heterostructure Barrier Varactor (HBV) diode and its use in frequency multiplier applications. Different aspects of material structures and frequency multipliers are described. The aim of the work presented is to develop design methods and processes to fabricate state-of-the-art planar HBVs and multipliers in the millimetre and submillimetre wave length region. Results from AlGaAs HBV frequency tripler measurements are presented. Simulations and cooled measurements show that excessive conduction current due to self-heating degrades the multiplier efficiency. A new design of planar GaAs-based HBVs with reduced thermal resistance and series resistance have been fabricated. A state-of-the-art performance of 4,8% efficiency and an output power of 4 mW at 246 GHz was achieved. A novel fabrication process where HBV diodes are fabricated on a copper substrate is proposed. This reduces thermal resistance and parasitic resistance without degrading the electrical characteristics. A 141 GHz quasi-optical HBV tripler is presented. A peak flange-to-flange efficiency of 8% and an output power of 11,5 mW was achieved. Different III-V material systems for HBVs have been tested. The results of lattice matched and pseudomorphic GaAs/AlGaAs, InGaAs/InAlAs, InAs/AlSb and phosphide containing materials for HBVs are presented. The state-of-the-art material for millimetre and submillimetre wave HBVs is the In0,53GaAs/In0,52AlAs system with a thin AlAs layer (30 Å) in the middle of the barrier. Both simple analytical models and a self-consistent Poisson/Schroedinger approach are used to predict and optimise HBV diodes. Finally, a simple quick-design method for calculation of optimum embedding impedances, optimum conversion efficiency and pump power for HBV triplers are presented.
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| 24. |
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