Cool running semiconductors

December 07, 2002

Solid-state semiconductors don't handle heat very well. If they're operated at high power they tend to burn out. Heat poses other problems as well--the hotter the device, the greater the electrical resistance (and the lower the efficiency).

Digital semiconductor devices also have capacitive elements--small elements that store electrical charge--and if the devices are to run at their fastest, these capacitive elements must be charged as rapidly as possible. Here again heat poses a dilemma: faster charging requires higher voltages and currents, but the resulting resistive heating raises the device's ambient temperature.

Increasing thermal conductivity can remove this extra heat faster, which in turn allows devices and circuits to be driven with a higher current-speed. Alternatively (without increasing the current), increasing thermal conductivity also allows devices to be more closely packed, which increases the system's overall speed (by reduced interconnect resistances and capacitances) thus improving time constants and circuit speed.

Under an Office of Naval Research basic research effort, Dr. George Brandes' team at Advanced Technology Materials Inc. (ATMI) of Danbury, CT have grown thin layer silicon from isotopically purified silane gas (Si28H4). Using the latest scanning thermal conductivity probe Prof. Fred Pollack of the City University of New York (also funded by ONR) measured the thermal conductivity of these silicon films at room temperature to be ~30% higher than regular silicon. Removing the Si27 and Si29 isotopes allows a purer phonon (improved lattice vibrational frequency) distribution, smoothing the pathway for heat conduction.

"ONR hopes to further this approach in isotopically pure silicon carbide for extremely high power devices," say ONR's Colin Wood, science manager for the research.
For more information on this research, or to interview Colin Wood if you are media, please contact John Petrik at 703-696-5031 or email

Office of Naval Research

Related Thermal Conductivity Articles from Brightsurf:

Clemson researchers decode thermal conductivity with light
Clemson researchers examine a highly efficient thermoelectric material in a new way - by using light.

Collaboration sparks new model for ceramic conductivity
As insulators, metal oxides - also known as ceramics - may not seem like obvious candidates for electrical conductivity.

Topology-optimized thermal cloak-concentrator
Cloaking a concentrator in thermal conduction via topology optimization. A simultaneous cloaking and concentrating of heat flux is achieved through topology optimization, a computational structural design methodology.

Investigating a thermal challenge for MOFs
New research led by an interdisciplinary team across six universities examines heat transfer in MOFs and the role it plays when MOFs are used for storing fuel.

Thermal manipulation of plasmons in atomically thin films
Nanoscale photothermal effects can induce substantial changes in the optical response experienced by the probing light, thus suggesting their applications in all-optical light modulation.

Making plastic more transparent while also adding electrical conductivity
In an effort to improve large touchscreens, LED light panels and window-mounted infrared solar cells, researchers at the University of Michigan have made plastic conductive while also making it more transparent.

Extremely low thermal conductivity in 1D soft chain structure BiSeX (X = Br, I)
Researchers found a new sort of simple one-dimensional (1D) crystal structured bismuth selenohalides (BiSeX, X = Br, I) with extremely low thermal conductivity.

Minimizing thermal conductivity of crystalline material with optimal nanostructure
Japanese researchers successfully minimized thermal conductivity by designing, fabricating, and evaluating the optimal nanostructure-multilayer materials through materials informatics (MI), which combines machine learning and molecular simulation.

Scientists measured electrical conductivity of pure interfacial water
Skoltech scientists in collaboration with researchers from the University of Stuttgart, the Karlsruhe Institute of Technology and the Russian Quantum Center achieved the first systematic experimental measurements of the electrical conductivity of pure interfacial water, hence producing new results significantly extending our knowledge of interfacial water.

Atomic magnetometer points to better picture of heart conductivity
Mapping the electrical conductivity of the heart would be a valuable tool in diagnosis and disease management, but doing so would require invasive procedures, which aren't capable of directly mapping dielectric properties.

Read More: Thermal Conductivity News and Thermal Conductivity Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to