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Silicon Carbide JFET Integrated Circuit Technology for High-Temperature Sensors

Patil, Amita C.

Abstract Details

2009, Doctor of Philosophy, Case Western Reserve University, EECS - Electrical Engineering.
N-channel, 6H-SiC depletion-mode JFETs have been designed and characterized for high-temperature integ,rated circuit applications. The electrical characteristics of the JFETs have been measured from 25°C to 600°C and match predictions of an abrupt-junction, long-channel JFET model. The extracted threshold voltage has a temperature dependence of about -1.9 mV/°C for temperatures up to 450°C. On one wafer, forty transistors were characterized, the extracted pinch-off current has a mean of 0.41 mA and standard deviation of ~0.10 mA, whereas threshold voltage has a mean of -8.5 V and standard deviation of ~1.0 V. The characterization of differential pairs and hybrid amplifiers constructed using these transistors is also reported. A three-stage amplifier with passive loads has a differential voltage gain of 50 dB and a unity-gain frequency of 200 kHz at 450°C, limited by test parasitics. A two-stage amplifier with active loads has reduced sensitivity to off-chip parasitics and exhibits a differential voltage gain of 69 dB with a unity-gain frequency of 1.3 MHz at 450°C. Feasibility of the 6H-SiC JFET integrated circuit technology for high-temperature analog circuits is demonstrated with a number of amplifier design examples. A single-stage amplifier with resistor loads has differential voltage gain ~36 dB and unity-gain frequency ~2.8 MHz at 600°C with remarkably stable voltage gain, i.e. less than 1 dB variation from 25°C to 600°C. A single-stage amplifier with current-source loads has differential voltage gain ~39 dB and unity-gain frequency ~2.1 MHz at 450°C. A single-stage amplifier with current-source loads, cascoded driver, and common-mode feedback has a differential voltage gain ~44.4 dB, unity-gain frequency ~2.8 MHz, and less than 1.4 dB gain variation for temperatures up to 450°C. A two-stage amplifier with current-source loads in the 1st stage and resistor loads in the 2nd stage has a differential mode gain of about 69 dB, and unity-gain frequency of 1.4 MHz at 576°C, and less than ~3.6 dB gain variation from 25°C to 576°C. A single-stage, single-ended transimpedance amplifier has low-frequency gain ~207 kΩ at room temperature and ~1.1 MΩ at 450°C, and gain variation for copies on a 6 mm x 6 mm die is within 2%.
Steven Garverick (Committee Chair)
Mehran Mehregany (Committee Member)
Walter Lambrecht (Committee Member)
Pedram Mohseni (Committee Member)
178 p.

Recommended Citations

Citations

  • Patil, A. C. (2009). Silicon Carbide JFET Integrated Circuit Technology for High-Temperature Sensors [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1238786695

    APA Style (7th edition)

  • Patil, Amita. Silicon Carbide JFET Integrated Circuit Technology for High-Temperature Sensors. 2009. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1238786695.

    MLA Style (8th edition)

  • Patil, Amita. "Silicon Carbide JFET Integrated Circuit Technology for High-Temperature Sensors." Doctoral dissertation, Case Western Reserve University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1238786695

    Chicago Manual of Style (17th edition)