| 1. |
- Lim, Jang-Kwon, et al.
(author)
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Temperature-dependent characteristics of 4H-SiC buried grid JBS diodes
- 2015
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In: Materials Science Forum. - : Trans Tech Publications Inc.. - 9783038354789 ; 821/823, s. 600-603
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Conference paper (peer-reviewed)abstract
- 4H-SiC Schottky Barrier Diodes (SBD) have been developed using p-type buried grids (BGs) formed by Al implantation. In order to reduce on-state resistance and improve forward conduction, the doping concentration of the channel region between the buried grids was increased. The fabricated diodes were encapsulated with TO-254 packages and electrically evaluated. Experimental forward and reverse characteristics were measured in the temperature range from 25 °C to 250 °C. On a bare die level, the forward voltage drop was reduced from 5.36 V to 3.90 V at 20 A as the channel doping concentration was increased in order to reduce the channel resistance. After encapsulation in a TO-254 package, the forward voltage drop was decreased by approximately 10% due to a lower contact resistance. The on-state resistance of an identical device measured on the bare die and in the TO-254 package increased with increasing temperature due to the decreased electron mobility in the drift region resulting in higher resistance. The incremental contact resistances of the bare dies were larger than in the packaged devices. One key issue associated with conventional Junction Barrier Schottky (JBS) diodes is a high leakage current at high temperature operation over 200 °C. The developed Buried Grid JBS (BG JBS) diode has significantly reduced leakage current due to a better field shielding at the Schottky contact. The leakage current of the packaged BG JBS diodes is compared to conventional SBD and commercial JBS diodes.
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| 2. |
- Wang, Qin, et al.
(author)
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Recent developments in electroabsorption modulators at Acreo Swedish ICT
- 2015
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In: Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications VIII. - : SPIE.
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Conference paper (peer-reviewed)abstract
- Three types of electroabsorption modulators (EAMs) based on III-V semiconductor multiple quantum wells (MQW) are presented in this work. One is a novel monolithic integration traveling-wave EAM for an analog optical transmitter/transceiver to achieve integrated photonic mm-wave functions for broadband connectivity. Another one is composed of an integrated EAM 1D array in a photonic beam-former as a Ku-band phased array antenna for seamless aeronautical networking through integration of data links, radios, and antennas. The third one addresses the use of MQW EAMs in free space optical links through biological tissue for transcutaneous communication.
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| 3. |
- Zhang, Andy Zhenzhong, et al.
(author)
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Fabrication of an electro-absorption transceiver with a monolithically integrated optical amplifier for fiber transmission of 40-60 GHz radio signals
- 2011
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In: Semiconductor Science and Technology. - : IOP Publishing. - 0268-1242 .- 1361-6641. ; 26:1, s. 014042-
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Journal article (peer-reviewed)abstract
- We report on the fabrication of a monolithically integrated semiconductor optical amplifier (SOA) and a reflective electro-absorption transceiver (EAT) for 40-60 GHz radio-over-fiber applications. The EAT can either function as a transmitter (reflective modulator) or as a receiver (photodetector) depending on operation mode. The SOA and the EAT sections are based on different InGaAsP multiple quantum-well active layers connected by a butt joint. Benzocyclobutene is used to reduce the capacitance beside the ridge mesa. Devices are designed to have a peaked response at the operating frequency through the design of microwave waveguides on top of the devices. The packaged device exhibits at 0.1 mW optical input power an amplified DC responsivity of 18.5 mA mW(-1) and a modulation efficiency of 0.67 mW V-1. The estimated radio frequency loss at 40 GHz of an optical link consisting of two SOA-EAT devices was 23 dB using an unmodulated optical input carrier to the transmitter of 0.94 mW.
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| 4. |
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| 5. |
- Zhang, Andy Zhenzhong, et al.
(author)
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Planarization of epitaxial SiC trench structures by plasma ion etching
- 2015
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In: Materials Science Forum. - 0255-5476 .- 1662-9752. - 9783038354789 ; 821-823, s. 549-552
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Journal article (peer-reviewed)abstract
- In this work, we present a planarization concept for epitaxial SiC trench structures involving reactive ion etching (RIE) and inductive coupled plasma (ICP) dry etching. The general idea is to transfer the flat surface from spun-on BCB/photo-resist layers to deposited silicon dioxide and finally to bulk SiC by applying process conditions with the same etch rate for the different materials. In this way several microns of unwanted material can be removed and planar SiC surfaces are obtained. With this method trench structures filled by epitaxial re-growth can be planarized with smooth surfaces and good homogeneity over the wafer. Cost-efficient device manufacturing can be achieved by using standard semiconductor process equipment. This technology makes it possible to manufacture advanced epitaxial SiC material structures for devices such as trench JBS diodes and double-gate trench JFETs.
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