Glenn Møller-Holst wrote:
....
> Et lag grafit eller kulstof-nanorør skulle være det bedste til at sprede
> varmen fra det småforurenede raffinerede sand (silicium, cpu/ic-chips):
>
> February 20th, 2008, Graphene Takes the Heat:
>
http://www.physorg.com/news122732528.html
> Citat: "...
> Carbon nanotubes have a typical thermal conductivity range of 3000 to
> 3500 W/m•K. Diamond, another form of carbon, comes in between 1000 and
> 2200 W/m•K. The single-layer graphene studied by the UCR researchers
> displayed a thermal conductivity as high as 5300 W/m•K near room
> temperature.
>
> “Graphene is particularly promising as a thermal management material
> because its superior thermal conductivity is supplemented by plane
> geometry and good integration with silicon,” added Balandin.
> ...."
>
> Intel har allerede patenteret ideen:
>
> Carbon-carbon and/or metal-carbon fiber composite heat spreaders.
> United States Patent 6837306
>
http://www.freepatentsonline.com/6837306.html
> (bladr forbi det tomme afsnit efter Google annoncerne)
> Citat: "...
> This invention relates to semiconductor manufacturing technology
> generally, and more specifically, to heat spreader technology for heat
> dissipation in a semiconductor [<-dansk halvleder] package
> ...."
>
> hilsen
>
> Glenn
....
Hej Brian
I øvrigt kunne man ligeså godt anvende superrent diamant eller
siliciumcarbid, da kulstof-indholdet gør at chip bedre leder varme og
kan tåle højere temperaturer. Superrent diamant er en halvleder.
"Beskidt"/amorft kulstof anvendes i kulstofmodstande og grafit anvendes
i motor-"kul":
Jul 08, 2004, GE Develops High Performance Carbon Nanotube Diode:
http://www.spacedaily.com/news/nanotech-04zx.html
Electrical properties of carbon nanotube FETs:
http://www.iop.org/EJ/article/1742-6596/109/1/012002/jpconf8_109_012002.pdf
2004-2005, Diamond semiconductor technology for RF device applications:
https://research.sabanciuniv.edu/269/1/3011800000828.pdf
Citat: "...
Based on our literature survey, we concluded that, despite the
technological challenges and few mentioned examples, diamond can
seriously be considered as a base material for RF electronics,
especially RF power circuits, where the important parameters are high
speed, high power density, efficient thermal management and low signal
loss in high power/frequencies.
....
briefly summarize some theoretical aspects for comparison with other
technologies:
* fmax is theoretically 53 times better than Si for n-type
diamond (42 times in p-type);
* Maximum breakdown voltage of a diamond power device is 514 times
higher than Si (This is 56 for 6H-SiC, 46 for 4H–SiC and 34 for GaN);
* Thermal conductivity; diamond leads other materials by at least a
factor of five;
* The Figure of Merit values, defined for high temperature, power and
frequency operations of devices, for diamond are at least 40–50 times
more than any other semiconductor.
...."
25 August, 2004, Door open for silicon replacement:
http://news.bbc.co.uk/1/hi/sci/tech/3598836.stm
Citat: "...Previous research has already shown that even at red-hot
temperatures as high as 650C (1,202F), silicon carbide devices can
function unperturbed and without the need for cooling....One exciting
application for silicon carbide could be in deep-space missions, where
nuclear power would be needed for the craft. Radiation-hardened silicon
carbide devices would reduce the shielding needed to protect reactor
control electronics..."
Infineon Technologies Produces Worlds first Power Semiconductors in
Silicon Carbide:
http://web.archive.org/web/20030106023250/www.chipcenter.com/power/powp364.html
Citat: "...Due to its unique characteristics, the silicon carbide (SiC)
material has high blocking voltage capability (up to 3500V) resulting in
a higher schottky barrier, ten times higher electrical breakdown field
strength, and a thermal conductivity comparable with that of copper..."
SiC baserede Schottky-dioder kan f.eks. købes her:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=1376383&keywords=diode%20SiC
Citat: "...
Reverse Recovery Time (trr) 0 ns
...."
De bedste silicium baserede effekt Schottky-dioders Reverse Recovery
Time er omkring ca. 25–50 nSek.
Mar 1, 2003, Power Electronics: SiC Schottky Diodes Improve Boost
Converter Performance:
http://powerelectronics.com/mag/power_sic_schottky_diodes/index.html
Citat: "...The switchmode power supply (SMPS) accounts for more than 10%
of the total system weight in a typical portable computer...Replacing a
conventional ultra-fast Si diode with an SiC Schottky diode at 140 kHz
(point 1) reduces the total power loss by 8.7W at 400W output power
(about 2% more efficiency)..."
hilsen
Glenn