| 1. |
- Ekström, Mattias, et al.
(författare)
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Low temperature Ni-Al ohmic contacts to p-TYPE 4H-SiC using semi-salicide processing
- 2018
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Ingår i: International Conference on Silicon Carbide and Related Materials, ICSCRM 2017. - : Trans Tech Publications. - 9783035711455 ; , s. 389-392
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Konferensbidrag (refereegranskat)abstract
- Most semiconductor devices require low-resistance ohmic contact to p-type doped regions. In this work, we present a semi-salicide process that forms low-resistance contacts (~10-4 Ω cm2) to epitaxially grown p-type (>5×1018 cm-3) 4H-SiC at temperatures as low as 600 °C using rapid thermal processing (RTP). The first step is to self-align the nickel silicide (Ni2Si) at 600 °C. The second step is to deposit aluminium on top of the silicide, pattern it and then perform a second annealing step in the range 500 °C to 700 °C.
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| 2. |
- Hussain, Muhammad Waqar, 1985-, et al.
(författare)
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A 500 °C Active Down-Conversion Mixer in Silicon Carbide Bipolar Technology
- 2018
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Ingår i: IEEE Electron Device Letters. - : IEEE Press. - 0741-3106 .- 1558-0563. ; 39:6, s. 855-858
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Tidskriftsartikel (refereegranskat)abstract
- This letter presents an active down-conversion mixer for high-temperature communication receivers. The mixer is based on an in-house developed 4H-SiC BJT and down-converts a narrow-band RF input signal centered around 59 MHz to an intermediate frequency of 500 kHz. Measurements show that the mixer operates from room temperature up to 500 °C. The conversion gain is 15 dB at 25 °C, which decreases to 4.7 dB at 500 °C. The input 1-dB compression point is 1 dBm at 25 °C and −2.5 dBm at 500 °C. The mixer is biased with a collector current of 10 mA from a 20 V supply and has a maximum DC power consumption of 204 mW. High-temperature reliability evaluation of the mixer shows a conversion gain degradation of 1.4 dB after 3-hours of continuous operation at 500 °C.
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| 3. |
- Hussain, Muhammad Waqar, 1985-, et al.
(författare)
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An Intermediate Frequency Amplifier for High-Temperature Applications
- 2018
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Ingår i: IEEE Transactions on Electron Devices. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9383 .- 1557-9646. ; 65:4, s. 1411-1418
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a two-stage small signal intermediate frequency amplifier for high-temperature communication systems. The proposed amplifier is implemented using in-house silicon carbide bipolar technology. Measurements show that the proposed amplifier can operate from room temperature up to 251 °C. At a center frequency of 54.6 MHz, the amplifier has a gain of 22 dB at room temperature, which decreases gradually to 16 dB at 251 °C. Throughout the measured temperature range, it achieves an input and output return loss of less than-7 and-11 dB, respectively. The amplifier has a 1-dB output compression point of about 1.4 dBm, which remains fairly constant with temperature. Each amplifier stage is biased with a collector current of 10 mA and a base-collector voltage of 3 V. Under the aforementioned biasing, the maximum power dissipation of the amplifier is 221 mW.
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| 4. |
- Hussain, Muhammad Waqar, 1985-, et al.
(författare)
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Silicon Carbide BJT Oscillator Design Using S-Parameters
- 2018
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Ingår i: European Conference on Silicon Carbide and Related Materials (ECSCRM), Birmingham September 2-6, 2018..
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Konferensbidrag (refereegranskat)abstract
- Radio frequency (RF) oscillator design typically requires large-signal, high-frequency simulation models for the transistors. The development of such models is generally difficult and time consuming due to a large number of measurements needed for parameter extraction. The situation isfurther aggravated as the parameter extraction process has to be repeated at multiple temperature points in order to design a wide-temperature range oscillator. To circumvent this modelling effort, analternative small-signal, S-parameter based design method can be employed directly without goinginto complex parameter extraction and model fitting process. This method is demonstrated through design and prototyping a 58 MHz, high-temperature (HT) oscillator, based on an in-house 4H-SiC BJT. The BJT at elevated temperature (up to 300 0C) was accessed by on-wafer probing and connectedby RF-cables to the rest of circuit passives, which were kept at room temperature (RT).
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| 5. |
- Kargarrazi, S., et al.
(författare)
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500 °c, High Current Linear Voltage Regulator in 4H-SiC BJT Technology
- 2018
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Ingår i: IEEE Electron Device Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 0741-3106 .- 1558-0563. ; 39:4, s. 548-551
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Tidskriftsartikel (refereegranskat)abstract
- This letter reports on a fully integrated 2-linear voltage regulator operational in a wide temperature range from 25 °C up to 500 °C fabricated in 4H-SiC technology. The circuit provides a stable output voltage with less than 1% variation in the entire temperature range. This letter demonstrates the first power supply solution providing both high-temperature (up to 500 °C) and high-load driving capabilities (up to 2).
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| 6. |
- Salemi, Arash, et al.
(författare)
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15 kV-Class Implantation-Free 4H-SiC BJTs With Record High Current Gain
- 2018
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Ingår i: IEEE Electron Device Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 0741-3106 .- 1558-0563. ; 39:1, s. 63-66
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Tidskriftsartikel (refereegranskat)abstract
- Implantation-free mesa-etched ultra-high-voltage (0.08 mm(2)) 4H-SiC bipolar junction transistors (BJTs) with record current gain of 139 are fabricated, measured, and analyzed by device simulation. High current gain is achieved by optimized surface passivation and optimal cell geometries. The area-optimized junction termination extension is utilized to obtain a high and stable breakdown voltage without ion implantation. The open-base blocking voltage of 15.8 kV at a leakage current density of 0.1 mA/cm(2) is achieved. Different cell geometries (single finger, square, and hexagon cell geometries) are also compared.
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| 7. |
- Salemi, Arash, et al.
(författare)
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Conductivity modulated and implantation-free 4H-SiC ultra-high-voltage PiN Diodes
- 2018
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Ingår i: International Conference on Silicon Carbide and Related Materials, ICSCRM 2017. - : Trans Tech Publications Inc.. - 9783035711455 ; , s. 568-572
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Konferensbidrag (refereegranskat)abstract
- Implantation-free mesa etched ultra-high-voltage 4H-SiC PiN diodes are fabricated, measured and analyzed by device simulation. The diode’s design allows a high breakdown voltage of about 19.3 kV according to simulations. No reverse breakdown is observed up to 13 kV with a very low leakage current of 0.1 μA. A forward voltage drop (VF) and differential on-resistance (Diff. Ron) of 9.1 V and 41.4 mΩ cm2 are measured at 100 A/cm2, respectively, indicating the effect of conductivity modulation.
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| 8. |
- Shakir, Muhammad, et al.
(författare)
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Electrical characterization of integrated 2-input TTL NAND Gate at elevated temperature, fabricated in bipolar SiC-technology
- 2018
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Ingår i: International Conference on Silicon Carbide and Related Materials, ICSCRM 2017. - : Trans Tech Publications Inc.. - 9783035711455 ; , s. 958-961
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Konferensbidrag (refereegranskat)abstract
- This work presents the design and electrical characterization of in-house-fabricated 2-input NAND gate. The monolithic bipolar 2-input NAND gate employing transistor-transistor logic (TTL) is demonstrated in 4H-SiC and operates over a wide range of temperature and supply voltage. The fabricated circuit was characterized on the wafer by using a hot-chuck probe-station from 25 °C up to 500 °C. The circuit is also characterized over a wide range of voltage supply i.e. 11 to 20 V. The output-noise margin high (NMH) and output-noise margin low (NML) are also measured over a wide range of temperatures and supply voltages using voltage transfer characteristics (VTC). The transient response was measured by applying two square waves of, 5 kHz and 10 kHz. It is demonstrated that the dynamic parameters of the circuit are temperature dependent. The 2-input TTL NAND gate consumes 20 mW at 500 °C and 15 V.
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