Temperature (T) is probably the most fundamental parameter in all kinds of science. Respective sensors are widely used in daily life. Besides conventional thermometers, optical sensors are considered to be attractive alternatives for sensing and on-line monitoring of T. This Review article focuses on all kinds of luminescent probes and sensors for measurement of T, and summarizes the recent progress in their design and application formats. The introduction covers the importance of optical probes for T, the origin of their T-dependent spectra, and the various detection modes. This is followed by a survey on (a) molecular probes, (b) nanomaterials, and (c) bulk materials for sensing T. This section will be completed by a discussion of (d) polymeric matrices for immobilizing T-sensitive probes and (e) an overview of the various application formats of T-sensors. The review ends with a discussion on the prospects, challenges, and new directions in the design of optical T-sensitive probes and sensors.

Luminescent probes and sensors for temperature.

The fact that wide bandgap semiconductors are capable of electronic functionality at much higher temperatures than silicon has partially fueled their development, particularly in the case of SiC. It appears unlikely that wide bandgap semiconductor devices will find much use in low-power transistor applications until the ambient temperature exceeds approximately 300/spl deg/C, as commercially available silicon and silicon-on-insulator technologies are already satisfying requirements for digital and analog VLSI in this temperature range. However practical operation of silicon power devices at ambient temperatures above 200/spl deg/C appears problematic, as self-heating at higher power levels results in high internal junction temperatures and leakages. Thus, most electronic subsystems that simultaneously require high-temperature and high-power operation will necessarily be realized using wide bandgap devices, once they become widely available. Technological challenges impeding the realization of beneficial wide bandgap high ambient temperature electronics, including material growth, contacts, and packaging, are briefly discussed.

High-temperature electronics - a role for wide bandgap semiconductors?

The physical and chemical properties of wide bandgap semiconductors silicon carbide and diamond make these materials an ideal choice for device fabrication for applications in many different areas, e.g. light emitters, high temperature and high power electronics, high power microwave devices, micro-electromechanical system (MEMS) technology, and substrates. These semiconductors have been recognized for several decades as being suitable for these applications, but until recently the low material quality has not allowed the fabrication of high quality devices. Silicon carbide and diamond based electronics are at different stages of their development. An overview of the status of silicon carbide's and diamond's application for high temperature electronics is presented.

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Silicon carbide and diamond for high temperature device applications

"Extreme environments" represents an important niche market for electronics and spans the operation of electronic components in surroundings lying outside the domain of conventional commercial, or even military, specifications. Such extreme environments would include, for instance, operation to very low temperatures (e.g., to 77 K or even 4.2 K), operation at very high temperatures (e.g., to 200/spl deg/C or even 300/spl deg/C), and operation in a radiation-rich environment (e.g., space). We argue that the unique bandgap-engineered features of silicon-germanium heterojunction bipolar transistors offer great potential to simultaneously satisfy all three extreme environment applications, potentially with little or no process modification, ultimately providing compelling cost advantages at the IC and system level.

On the Potential of SiGe HBTs for Extreme Environment Electronics

The higher voltage blocking capability and faster switching speed of silicon-carbide (SiC) mosfet s have the potential to replace Si insulated gate bipolar transistors (IGBTs) in medium-/low-voltage and high-power applications. In this paper, a state-of-the-art commercially available 325 A, 1700 V SiC mosfet module has been fully characterized under various load currents, bus voltages, and gate resistors to reveal their switching capability. Meanwhile, Si IGBT modules with similar power ratings are also tested under the same conditions. From the test results, several interesting points have been obtained: different to the Si IGBT module, the over-shoot current of the SiC mosfet module increases linearly with the increase of the load current and it has been explained by a model of the over-shoot current proposed in this paper; the induced negative gate voltage due to the complementary device turn- off (crosstalk effect) is more harmful to the SiC mosfet module than the induced positive gate voltage during turn- on when the gate off-voltage is –6 V; the maximum dv / dt and di / dt (electromagnetic interference) during switching transients of the SiC mosfet module are close to those of the Si IGBT module when the gate resistance is larger than 8 Ω but the switching loss of the SiC mosfet module is much smaller; the switching losses of the Si IGBT module are greater than those of the SiC mosfet module even when the gate resistance of the former is reduced to zero. An accurate power loss model, which is suitable for a three-phase two-level converter based on SiC mosfet modules considering the power loss of the parasitic capacitance, has been presented and verified in this paper. From the model, a 96.2% efficiency can be achieved at the switching frequency of 80 kHz and the power of 100 kW.

Performance Evaluation of High-Power SiC MOSFET Modules in Comparison to Si IGBT Modules

High-temperature electronics applications are found in combustion systems, well logging, industrial processes, air stagnation points in supersonic aircraft, vehicle brakes, nuclear reactors, and dense electronic packages. We summarize physical effects and materials issues important for reliable operation of semiconductor device technologies at high temperatures (> 125° C). We review the high-temperature potential of Si, GaAs, other III-V compounds, and SiC. For completeness, we also comment on nitrides, diamond, and vacuum microelectronics. We conclude that Si on insulator (SOI) technology can be developed readily for small signal operation up to about 300° C. There is some ongoing work in this area. GaAs offers little advantage over Si because of poor device isolation and the lack of reliable contacts above 250° C

An overview of high-temperature electronic device technologies and potential applications

High-temperature electronics applications are found in combustion systems, well logging, and industrial processes, air stagnation points in supersonic aircraft, vehicle brakes, nuclear reactors, and dense electronic packages. We summarize physical effects and materials issues important for reliable operation of semiconductor device technologies at high temperatures (>125/spl deg/C). We review the high-temperature potential of Si, GaAs, other III-V compounds, and SiC. For completeness, we also comment on nitrides, diamond, and vacuum microelectronics. We conclude that Si on insulator (SOI) technology can be developed readily for small signal operation up to about 300/spl deg/C. There is some ongoing work in this area. GaAs offers little advantage over Si because of poor device isolation and the lack of reliable contacts above 250/spl deg/C. Other III-V compounds could be developed for operation to /spl sim/600/spl deg/C, using processes similar to those used for optoelectronics. There may be a market niche for III-V power devices above 200/spl deg/C. There is considerable activity in semiconducting SiC, and device functionality has been demonstrated above 600/spl deg/C. SiC is promising for operation above 300/spl deg/C, and for power devices at frequencies from dc to /spl sim/10 GHz, but it faces numerous challenges to achieve manufacturable status. We attempt to match technologies with application areas. >

D. B. King

Papers

An overview of high-temperature electronic device technologies and potential applications

An overview of high-temperature electronic device technologies and potential applications