Papers by Keyword: MESFET

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Authors: Mihaela Alexandru, Viorel Banu, Phillippe Godignon, Miguel Vellvehi, José Millan
Abstract: The design and development of SiC integrated circuits (ICs) nowadays is a necessity due to the increasing demand for high temperature intelligent power applications and intelligent sensors. Due to the superior electrical, mechanical and chemical proprieties of 4H-SiC poly-type, 4H-SiC MESFET transistor is a good compromise for ICs on SiC able to work at higher temperatures (HT) than on Si. This paper presents new experimental results of approaching embedded logic gates with SiC MESFETs and resistors, built in junction-isolated tubs. The P+ implantation isolation technology offers important perspectives regarding the integration density of devices per unit area and wafer surface, being able to use far more complex design geometry for modeling ICs on SiC.
Authors: Jeong Hyuk Yim, Ho Keun Song, Jeong Hyun Moon, Han Seok Seo, Jong Ho Lee, Hoon Joo Na, Jae Bin Lee, Hyeong Joon Kim
Abstract: Planar MESFETs were fabricated on high-purity semi-insulating (HPSI) 4H-SiC substrates. The saturation drain current of the fabricated MESFETs with a gate length of 0.5 μm and a gate width of 100 μm was 430 mA/mm, and the transconductance was 25 mS/mm. The maximum oscillation frequency and cut-off frequency were 26.4 GHz and 7.2 GHz, respectively. The power gain was 8.4 dB and the maximum output power density was 2.8 W/mm for operation of class A at CW 2 GHz. MESFETs on HPSI substrates showed no current instability and much higher output power density in comparison to MESFETs on vanadium-doped SI substrates.
Authors: Joakim Eriksson, Niklas Rorsman, Herbert Zirath, Rolf Jonsson, Qamar-ul Wahab, Staffan Rudner
Authors: Joakim Eriksson, Niklas Rorsman, Herbert Zirath, Anne Henry, Björn Magnusson, Alexsandre Ellison, Erik Janzén
Authors: Hu Jun Jia, Yin Tang Yang, Chang Chun Chai
Abstract: Some new techniques include n- shielding, buried channel and field plate are firstly adopted together for design and fabrication of 4H-SiC microwave MESFETs. The testing results show that a relatively broad and uniform transconductance versus gate voltage was obtained using a 0.1m n- shielding. 0.3mm gate periphery device shows good DC and RF performance such as 5.27W/mm power density, 6.7dB power gain and 43% power added efficiency at 2.3GHz under pulse operation. Compared to conventional SiC MESFETs, a gate lag ratio as high as 0.84 can be achieved for the developed devices even under a nearly actual operating condition.
Authors: Wei Li Shi, Chen Yang Xue, Zhen Xin Tan, Jun Liu, Wen Dong Zhang
Abstract: An experimental investigation has been carried out with clarifying the external mechanical stress effect on GaAs metal-semiconductor field-effect transistor (MESFET) I-V characteristic curve which as the sensitive element of micro-accelerometer in different condition. In this paper, we research different channel directions to explore the output characteristics of the GaAs MESFET which fabricated at the root of the cantilever. We design three channel directions which angled with the cantilever as 0 degree, 45 degree, 90 degree. We find that when the Channel direction parallel to the cantilever direction, ∆U has the maximum value of 12.13mv. The sensitivity of 0 degree is 0.04mv/g higher than the 90 degree. The dynamic result indicates that the channel direction parallel to the cantilever direction is the optimized design structure.
Authors: S. Mitra, Jesse B. Tucker, Mulpuri V. Rao, N. Papanicolaou, Kenneth A. Jones
Authors: Olivier Noblanc, C. Arnodof, E. Chartier, Christian Brylinski
Authors: Per Åke Nilsson, A.M. Saroukhan, J.O. Svedberg, Andrey O. Konstantinov, S. Karlsson, C. Adås, U. Gustafsson, Chris I. Harris, Niklas Rorsman, Joakim Eriksson, Herbert Zirath
Authors: Kevin Matocha, Jesse B. Tucker, Ed Kaminsky
Abstract: Different SiC thermal oxide passivation techniques were characterized using UV-induced hysteresis to estimate the fixed charge, Qf, and interface-trapped charge, Qit. Steam-grown oxides have a fixed charge density of Qf=-1x1012 cm-2, and a net interface-trapped charge density of Qit=4x1011cm-2. Addition of a thin low-pressure chemical-vapor deposited (LPCVD) silicon nitride layer decreased these parameters to Qf=-2x1011 cm-2 and Qit=4x1010 cm-2. Dry oxide shows a fixed charge density, Qf=-3x1012 cm-2 and interface-trapped charge density, Qit=4x1011 cm-2 which changes to Qf=+7x1010 cm-2 and Qit=1x1010 cm-2 with the addition of a LPCVD silicon nitride cap. Dry thermal oxide with a silicon nitride cap was used to passivate SiC MESFETs to achieve a power-added efficiency of 60% in pulsed operation at 3 GHz in Class AB bias conditions.
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