High power electronic devices

Applied Sciences, Inc. has, in the past few years, used the fixed catalyst fiber to fabricate and analyze VGCF-reinforced composites which could be candidate materials for thermal management substrates in high density, high power electronic devices and space power system radiator fins and high performance applications such as plasma facing components in experimental nuclear fusion reactors. These composites include carbon/carbon (CC) composites, polymer matrix composites, and metal matrix composites (MMC). Measurements have been made of thermal conductivity, coefficient of thermal expansion (CTE), tensile strength, and tensile modulus. Representative results are described below. 

The record-high thermal conductivity of diamond makes it an obvious choice for consideration as a substrate for high power electronic devices. One method that has been successful in producing diamond films is chemical vapor deposition (CVD). The CVD diamond films are polycrystalline, but can still have k > 2000Wm" K . The high cost of diamond films still precludes their widespread use. 

McGlen, R., Jachuck, R. and Lin, S. (2003). Integrated thermal management techniques for high power electronic devices. Proc. 8th UK National Heat Transfer Conf., Oxford University. 

Both single-phase charging systems and three-phase charging systems would contain power electronic devices that as a side effect introduce waveform distortion and create power quality problems. Filtering devices used in conjunction with residential charging systems could be used to reduce harmonics and other power quality problems, but the cost of such filtering devices is currently quite high. 

Agarwal, SiC for Applications in High-Power Electronics R. J. Trew, SiC Microwave Devices... 

By far the biggest application for SiC technology is the high-power electronics market. It may not be as glamorous as the high-frequency or the optoelectronic markets but it is big. The current size of the power-device market is 16 billion [65] and it is growing at a rate of almost 10% per year [66]. The question on everyone s mind is how big will the SiC share be ... 

Most unmodified polymeric resins have a very low thermal conductivity. There are certain applications where high levels of thermal conductivity are required. For example, power electronic devices and other heat-generating components are bonded to heat sinks and other metal sources. Metal powder filled adhesives, such as those described above for electrically conductive adhesives, can conduct both heat and electricity. 

H-SiC is an indirect band-gap material that is produced commercially. As stated previously, 4H-SiC along with 6H-SiC are used for short-wavelength optoelectronic, high-temperature, radiation-resistant, and high-power/high-frequency electronic devices. 

One of the major markets for wide band-gap materials is in electronics. Specifically, they are suitable for and have been used for heat sinks (diamond), short wavelength optoelectronic devices (GaP, GaN, SiC), high-temperature electronics (SiC, GaN), radiation resistant devices, and high-power/high-frequency electronic devices (diamond, GaN, SiC). " Recent research showed that Mn-doped GaN can be used for spintro-nic applications.f" Atomically flat technology developed by NASA for SiC and GaN WBG material can introduce a new dimension of application for WBG materials. 

Passive two-phase heat transfer devices capable of transferring large quantities of heat with a minimal temperature drop were first introduced by Gaugler in 1944 [1]. These devices, however, received little attention until Grover et al. [2] published the results of an independent investigation and first applied the term heat pipe. Since that time, heat pipes have been employed in numerous applications ranging from temperature control of the permafrost layer under the Alaska pipeline to the thermal control of electronic components such as high-power semiconductor devices [3]. 

M. Thumm, State of the art of high power Gyro-devices and free-electron Masers, WLssenschaf-tliche Berichte FZKA 5564, Forschungszentrum Karlsruhe GmbH, Karlsruhe 1995, (ISSN 0947-8620). 

---