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Norman F. Prokop

Bio: Norman F. Prokop is an academic researcher from Glenn Research Center. The author has contributed to research in topics: JFET & Integrated circuit. The author has an hindex of 13, co-authored 43 publications receiving 449 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the fabrication and testing of the first semiconductor transistors and small-scale integrated circuits (ICs) to achieve up to 3000 h of stable electrical operation at 500degC in air ambient is reported.
Abstract: The fabrication and testing of the first semiconductor transistors and small-scale integrated circuits (ICs) to achieve up to 3000 h of stable electrical operation at 500degC in air ambient is reported. These devices are based on an epitaxial 6H-SiC junction field-effect transistor process that successfully integrated high-temperature ohmic contacts, dielectric passivation, and ceramic packaging. Important device and circuit parameters exhibited less than 10% of change over the course of the 500degC operational testing. These results establish a new technology foundation for realizing durable 500degC ICs for combustion-engine sensing and control, deep-well drilling, and other harsh-environment applications.

121 citations

Journal ArticleDOI
TL;DR: In this paper, short-term demonstrations of packaged 4H-SiC junction field effect transistor (JFET) logic integrated circuits (ICs) at temperatures exceeding 800 °C in air are reported, including a 26-transistor 11-stage ring oscillator that functioned at 961 °C ambient temperature.
Abstract: Short-term demonstrations of packaged 4H-SiC junction field-effect transistor (JFET) logic integrated circuits (ICs) at temperatures exceeding 800 °C in air are reported, including a 26-transistor 11-stage ring oscillator that functioned at 961 °C ambient temperature believed unprecedented for electrical operation of a semiconductor IC. The expanded temperature range should assist temperature acceleration testing/qualification of such ICs intended for long-term use in applications near 500 °C ambient, and perhaps spawn new applications. Ceramic package assembly leakage currents inhibited the determination of some intrinsic SiC device/circuit performance properties at these extreme temperatures, so it is conceivable that even higher operating temperatures might be obtained from SiC JFET ICs by employing packaging and circuit design intended/optimized for T $\ge800$ °C.

94 citations

13 May 2008
TL;DR: In this article, the fabrication and long-term 500 degrees Centigrade operation of 6H-SiC integrated circuits based on epitaxial 6HSiC junction field effect transistors (JFETs) was reported.
Abstract: The NASA Glenn Research Center is developing very high temperature semiconductor integrated circuits (ICs) for use in the hot sections of aircraft engines and for Venus exploration where ambient temperatures are well above the approximately 300 degrees Centigrade effective limit of silicon-on-insulator IC technology. In order for beneficial technology insertion to occur, such transistor ICs must be capable of prolonged operation in such harsh environments. This paper reports on the fabrication and long-term 500 degrees Centigrade operation of 6H-SiC integrated circuits based on epitaxial 6H-SiC junction field effect transistors (JFETs). Simple analog amplifier and digital logic gate ICs have now demonstrated thousands of hours of continuous 500 degrees Centigrade operation in oxidizing air atmosphere with minimal changes in relevant electrical parameters. Electrical characterization and modeling of transistors and circuits at temperatures from 24 degrees Centigrade to 500 degrees Centigrade is also described. Desired analog and digital IC functionality spanning this temperature range was demonstrated without changing the input signals or power supply voltages.

29 citations

Journal ArticleDOI
TL;DR: In this paper, the first stable electrical operation of semiconductor ICs for 1 year (8760 hours) at 500°C in air atmosphere was reported, achieving a more than 7-fold increase in circuit complexity from the 24 transistor ring oscillator ICs reported at HiTEC 2016.
Abstract: This work describes recent progress in the design, processing, upscaling, and testing of 500°C durable two-level interconnect 4H-SiC JFET IC technology undergoing development at NASA Glenn Research Center. For the first time, stable electrical operation of semiconductor ICs for 1 year (8760 hours) at 500°C in air atmosphere is reported. These groundbreaking durability results were attained on two-level interconnect JFET demonstration ICs with 175 or more transistors on each chip. This corresponds to a more than 7-fold increase in 500°C-durable circuit complexity from the 24 transistor ring oscillator ICs reported at HiTEC 2016.

25 citations

Journal ArticleDOI
TL;DR: In this article, a prototype 4H-SiC JFET IC was demonstrated without any change/adjustment of input signal levels or power supply voltages, which is expected to simplify infusion of this IC technology into a broader range of beneficial applications.
Abstract: Operational testing of prototype 4H-SiC JFET ICs across an unrivaled ambient temperature span in excess of 1000 °C, from -190 °C to +812 °C, has been demonstrated without any change/adjustment of input signal levels or power supply voltages. This unique ability is expected to simplify infusion of this IC technology into a broader range of beneficial applications.

23 citations


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01 Apr 1983

405 citations

Journal ArticleDOI
TL;DR: In this article, the performance of high voltage rectifiers and enhancement-mode metal-oxide field effect transistors on Ga2O3 has been evaluated and shown to benefit from the larger critical electric field relative to either SiC or GaN.
Abstract: Gallium oxide (Ga2O3) is emerging as a viable candidate for certain classes of power electronics with capabilities beyond existing technologies due to its large bandgap, controllable doping, and the availability of large diameter, relatively inexpensive substrates. These applications include power conditioning systems, including pulsed power for avionics and electric ships, solid-state drivers for heavy electric motors, and advanced power management and control electronics. Wide bandgap (WBG) power devices offer potential savings in both energy and cost. However, converters powered by WBG devices require innovation at all levels, entailing changes to system design, circuit architecture, qualification metrics, and even market models. The performance of high voltage rectifiers and enhancement-mode metal-oxide field effect transistors benefits from the larger critical electric field of β-Ga2O3 relative to either SiC or GaN. Reverse breakdown voltages of over 2 kV for β-Ga2O3 have been reported, either with or without edge termination and over 3 kV for a lateral field-plated Ga2O3 Schottky diode on sapphire. The metal-oxide-semiconductor field-effect transistors fabricated on Ga2O3 to date have predominantly been depletion (d-mode) devices, with a few demonstrations of enhancement (e-mode) operation. While these results are promising, what are the limitations of this technology and what needs to occur for it to play a role alongside the more mature SiC and GaN power device technologies? The low thermal conductivity might be mitigated by transferring devices to another substrate or thinning down the substrate and using a heatsink as well as top-side heat extraction. We give a perspective on the materials’ properties and physics of transport, thermal conduction, doping capabilities, and device design that summarizes the current limitations and future areas of development. A key requirement is continued interest from military electronics development agencies. The history of the power electronics device field has shown that new technologies appear roughly every 10-12 years, with a cycle of performance evolution and optimization. The older technologies, however, survive long into the marketplace, for various reasons. Ga2O3 may supplement SiC and GaN, but is not expected to replace them.

348 citations

Journal ArticleDOI
TL;DR: In this paper, the authors review the applications that are calling for high temperature electronics, discuss some of the underlying problems with standard technology, and examine the established and emerging technologies that provide solutions to engineers who wish to design high-temperature electronic systems.
Abstract: Electronics that must operate at extreme temperatures present a unique set of challenges that must be carefully addressed. We review the applications that are calling for high temperature electronics, discuss some of the underlying problems with standard technology, and examine the established and emerging technologies that provide solutions to engineers who wish to design high-temperature electronic systems.

215 citations

Journal ArticleDOI
TL;DR: The current state of wide bandgap device technology is reviewed and its impact on power electronic system miniaturization for a wide variety of voltage levels is described in this article, followed by an outline of the applications that stand to be impacted.
Abstract: The current state of wide bandgap device technology is reviewed and its impact on power electronic system miniaturization for a wide variety of voltage levels is described. A synopsis of recent complementary technological developments in passives, integrated driver, and protection circuitry and electronic packaging are described, followed by an outline of the applications that stand to be impacted. A glimpse into the future based on the current technological trends is offered.

192 citations

Journal ArticleDOI
10 Sep 2010-Science
TL;DR: A microfabricated electromechanical inverter with SiC complementary NEMS switches capable of operating at 500°C with ultralow leakage current is reported, a promising approach for low-power, high-performance logic operation at temperatures higher than 300°C, beyond the capability of conventional silicon technology.
Abstract: Logic circuits capable of operating at high temperatures can alleviate expensive heat-sinking and thermal-management requirements of modern electronics and are enabling for advanced propulsion systems. Replacing existing complementary metal-oxide semiconductor field-effect transistors with silicon carbide (SiC) nanoelectromechanical system (NEMS) switches is a promising approach for low-power, high-performance logic operation at temperatures higher than 300°C, beyond the capability of conventional silicon technology. These switches are capable of achieving virtually zero off-state current, microwave operating frequencies, radiation hardness, and nanoscale dimensions. Here, we report a microfabricated electromechanical inverter with SiC complementary NEMS switches capable of operating at 500°C with ultralow leakage current.

176 citations