| 11. |
- Elahipanah, Hossein, 1982-, et al.
(author)
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Modification of Etched Junction Termination Extension for the High Voltage 4H-SiC Power Devices
- 2016
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In: Materials Science Forum. - : Trans Tech Publications Inc.. - 0255-5476 .- 1662-9752. ; 858, s. 978-981
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Journal article (pop. science, debate, etc.)abstract
- High voltage 4H-SiC bipolar junction transistors (BJTs) with modified etched junction termination extension (JTE) are fabricated and optimized in terms of the length and remaining dose of JTEs. It is found that the JTE1 is the most effective one in spreading the electric field. Hence, for a given total termination length, a decremental JTE length from the innermost edge to the outermost mesa edge of the device results in better modification of the electric field. A breakdown voltage of 4.95 kV is measured for the modified device, which shows ~20% improvement of the termination efficiency for no extra cost or extra process step. Equal-size BJTs by interdigitated-emitter with different number of fingers and cell pitches are fabricated. It is presented that the maximum current gain decreases by having more fingers while the maximum current gain is achieved at higher current density.
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| 12. |
- Fahnestock, Jesse, 1974-, et al.
(author)
-
RISEnergy: Roadmaps for energy innovation in Sweden through 2030
- 2016
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Reports (other academic/artistic)abstract
- RISE Research Institutes of Sweden is a group of research and technology organisations. RISE is a leading innovation partner working global cooperation with academia, enterprise and society to create value, growth and competitiveness through research excellence and innovation.In the area of Energy, RISE has developed innovation Roadmaps covering:Energy Efficient TransportElectric Power SystemEnergy Efficient and Smart BuildingsSustainable Thermal ProcessesEfficient Energy Use in IndustryDecarbonisation of Basic IndustriesThese Roadmaps describe development pathways for technologies, non-technical elements (market design, user behaviours, policies, etc.) and key actors that deliver on a plausible, desirable vision for each respective innovation area in 2030. These Roadmaps are intended to support RISE’s strategic planning and development, but should be relevant reading for anyone interested in energy innovation in Sweden.
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| 13. |
- Fuglesang, Christer, 1957-, et al.
(author)
-
Working on venus and beyond - SiC electronics for extreme environments
- 2017
-
In: Proceedings of the International Astronautical Congress, IAC. - : International Astronautical Federation, IAF. - 9781510855373 ; , s. 10393-10398
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Conference paper (peer-reviewed)abstract
- Venus is our closest planet, but we know much less about it than about Mars. The main reason for this is the extreme conditions, with a dense atmosphere of mainly CO2 at 92 bar atmosphere and 460 °C temperature at the surface. Only six spacecraft have succeeded to land on Venus and transmit data back to Earth; however none survived for long due to the high temperature. Venera-13 has the record, with 127 minutes at the surface of Venus in 1982. There are many compelling reasons to learn more about the sister planet of Earth, which requires measurements over months rather than minutes on the surface of Venus. Perhaps the single-most challenging task for long-term data taking on the surface of Venus is to build electronics that can operate at temperatures up to 500 °C without cooling. It seems that such technology must be based on wide bandgap semiconductors, such as GaN, SiC or diamond. At KTH, research with SiC devices and integrated circuits has been done for more than 20 years, demonstrating high voltage devices and digital integrated circuit operation at 600 °C. In 2014 the project Working On Venus launched, with funding from Knut and Alice Wallenberg Foundation. The goal is to demonstrate all the electronics for a complete working lander, with all electronics from sensors through amplifiers and analog-to-digital converters to microcontroller with memory and radio, including power supply. The particular sensors the project has in mind are seismic, gas and image sensors. So far, a 200 device level integration has been demonstrated at 500 °C and a 5000+ device level 4 bit microcontroller is being fabricated in an in-house bipolar technology. As for all devices for space, radiation is another concern. SiC integrated circuits have survived exposure to 3 MeV protons with fluences of 1013 cm-2 and gamma rays with doses of 332 Mrad. The dedicated project SUPERHARD IC will study manufacture methods for radiation hardened instrument components that could go beyond Venus, for example for Jovian system exploration. Members of Working on Venus are discussing with scientists seeking opportunities for a Venus Long-Life Surface Package (lander). In 2016 a response was submitted to ESA's Call for New Scientific Ideas.
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| 14. |
- Hou, Shuoben, et al.
(author)
-
4H-SiC PIN diode as high temperature multifunction sensor
- 2017
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In: 11th European Conference on Silicon Carbide and Related Materials, ECSCRM 2016. - : Trans Tech Publications Ltd. - 9783035710434 ; , s. 630-633
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Conference paper (peer-reviewed)abstract
- An in-house fabricated 4H-SiC PIN diode that has both optical sensing and temperature sensing functions from room temperature (RT) to 550 ºC is presented. The two sensing functions can be simply converted from one to the other by switching the bias voltage on the diode. The optical responsivity of the diode at 365 nm is 31.8 mA/W at 550 ºC. The temperature sensitivity of the diode is 2.7 mV/ºC at the forward current of 1 μA.
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| 15. |
- Hou, Shuoben, et al.
(author)
-
550 degrees C 4H-SiC p-i-n Photodiode Array With Two-Layer Metallization
- 2016
-
In: IEEE Electron Device Letters. - : IEEE. - 0741-3106 .- 1558-0563. ; 37:12, s. 1594-1596
-
Journal article (peer-reviewed)abstract
- The p-i-n ultraviolet (UV) photodiodes based on 4H-SiC have been fabricated and characterized from room temperature (RT) to 550 degrees C. Due to bandgap narrowing at higher temperatures, the photocurrent of the photodiode increases by 9 times at 365 nm and reduces by 2.6 times at 275 nm from RT to 550 degrees C. Moreover, a 4H-SiC p-i-n photodiode array has been fabricated. Each column and row of the array is separately connected by two-layer metallization.
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| 16. |
- Hou, Shuoben, et al.
(author)
-
A 4H-SiC BJT as a Switch for On-Chip Integrated UV Photodiode
- 2019
-
In: IEEE Electron Device Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 0741-3106 .- 1558-0563. ; 40:1, s. 51-54
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Journal article (peer-reviewed)abstract
- This letter presents the design, fabrication, and characterization of a 4H-SiC n-p-n bipolar junction transistor as a switch controlling an on-chip integrated p-i-n photodiode. The transistor and photodiode share the same epitaxial layers and topside contacts for each terminal. By connecting the collector of the transistor and the anode of the photodiode, the photo current from the photodiode is switched off at low base voltage (cutoff region of the transistor) and switched on at high base voltage (saturation region of the transistor). The transfer voltage of the circuit decreases as the ambient temperature increases (2 mV/degrees C). Both the on-state and off-state current of the circuit have a positive temperature coefficient and the on/off ratio is >80 at temperature ranged from 25 degrees C to 400 degrees C. It is proposed that the on/off ratio can be increased by similar to 1000 times by adding a light blocking layer on the transistor to reduce light induced off-state current in the circuit.
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| 17. |
- Hou, Shuoben, et al.
(author)
-
High Temperature High Current Gain IC Compatible 4H-SiC Phototransistor
- 2019
-
Conference paper (peer-reviewed)abstract
- This paper presents our in-house fabricated 4H-SiC n-p-n phototransistors. The wafer mapping of the phototransistor on two wafers shows a mean maximum forward current gain (βFmax) of 100 at 25 ºC. The phototransistor with the highest βFmax of 113 has been characterized from room temperature to 500 ºC. The βFmax drops to 51 at 400 ºC and remains the same at 500 ºC. The photo current gain of the phototransistor is 3.9 at 25 ºC and increases to 14 at 500 ºC under the 365 nm UV light with the optical power of 0.31 mW. The processing of the phototransistor is same to our 4HSiC-based bipolar integrated circuits, so it is a promising candidate for 4H-SiC opto-electronics onchip integration.
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| 18. |
- Hou, Shuoben, et al.
(author)
-
Process Control and Optimization of 4H-SiC Semiconductor Devices and Circuits
- 2019
-
In: Proceedings of the 3rd Electron Devices Technology and Manufacturing, (EDTM) Conference 2019. - : IEEE.
-
Conference paper (peer-reviewed)abstract
- Processing techniques for 4H-SiC devices and circuits are optimized. The SiC mesa etching process has a variation of < 5% over the wafer. The average n-type contact resistivity is 1.15 × 10-6 Ohm.cm2. The fabricated devices and circuits with one-layer metal interconnect have high yield with no need of chemical-mechanical planarization process. More complex circuits with two-layer metal interconnect achieve high yield by applying chemical-mechanical planarization process.
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| 19. |
- Hou, Shuoben, et al.
(author)
-
Scaling and modeling of high temperature 4H-SiC p-i-n photodiodes
- 2018
-
In: IEEE Journal of the Electron Devices Society. - : Institute of Electrical and Electronics Engineers Inc.. - 2168-6734. ; 6:1, s. 139-145
-
Journal article (peer-reviewed)abstract
- 4H-SiC p-i-n photodiodes with various mesa areas (40,000μm2, 2500μm2, 1600μm2, and 400μm2) have been fabricated. Both C-V and I-V characteristics of the photodiodes have been measured at room temperature, 200 °C, 400 °C, and 500 °C. The capacitance and photo current (at 365 nm) of the photodiodes are directly proportional to the area. However, the dark current density increases as the device is scaled down due to the perimeter surface recombination effect. The photo to dark current ratio at the full depletion voltage of the intrinsic layer (-2.7 V) of the photodiode at 500 °C decreases 7 times as the size of the photodiode scales down 100 times. The static and dynamic behavior of the photodiodes are modeled with SPICE parameters at the four temperatures.
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| 20. |
- Hou, Shuoben, et al.
(author)
-
Scaling of 4H-SiC p-i-n photodiodes for high temperature applications
- 2017
-
In: 2017 75th Annual Device Research Conference (DRC). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509063277
-
Conference paper (peer-reviewed)abstract
- Ultraviolet (UV) detection is important in astronomy, combustion detections and medical analysis. Solid-state UV detectors based on wide band gap semiconductors, such as 4H-SiC, are widely studied because of their excellent electrical properties [1]. 4H-SiC based UV detectors are solar blind and can be applied in extremely high temperature environments [2]. However, the state-of-art 4H-SiC photodetectors still have large sizes (>10000 μm2), which are not suitable to be integrated into high resolution UV photography sensors. To build a full-frame UV imaging sensor containing megapixels, photodiodes smaller than 20 μm by side are necessary. Here, we report the fabrication and characterization of 4H-SiC p-i-n photodiodes with mesa areas scaled from 40000 μm2 to 400 μm2. The relationships between the parameters and the areas of the photodiodes are discussed. The photodiodes are fully functional from room temperature (RT) to 500 °C.
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