Comments on: Tiny transistor may become conductor king

By: Buk

Buk — Thu, 14 Jan 2010 04:11:39 +0000

I wonder if this material functions as well after an electro magnetic pulse? Might be one of may reasons the military might be funding it. Maybe it doesn’t “fry” as easily as the current semi conductors under those conditions.

By: wjv

wjv — Tue, 05 Jan 2010 16:27:07 +0000

Mr. Gaffer:
the volts per area measurement given here is a rather standard metric for semiconductor materials because they are almost always manufactured in disks/slides (i.e. flat and with small uniform thicknesses). It is more typical to give resistance per unit area (a.k.a. sheet resistance) however these are proportionately related via ohm’s law so its preference really.

Sheet resistance is simply resistivity with the thickness dimension neglected for simplicity. This metric is convenient because it turns an extensive property (resistance) of a material into an intensive property (sheet resistance or resistivity) so that one can compare apples to apples with various semiconductor materials.

By: Gray Gaffer

Gray Gaffer — Thu, 17 Dec 2009 00:37:14 +0000

I’m a little confused about the “3 million Volts per square centimeter”. I have not seen this metric before. I can believe a metric of a voltage gradient of 3×10^6 V/cm i.e. vertically through the junction material, but it does not seem right to me that surface area should affect the breakdown voltage.

I would also like some indication of scale in the operating voltage vs max Ic current, and also capacitance effects related to switching speed and swing amplitude. There’s no point raising the operating voltage beyond the power consumption of today’s standard Si based technologies, which is why they are heading to less than 1 volt operating after having started out at 5 volts, when the power consumption is so closely related to operating speed x operating voltage x node capacitance.

Of course, this is moot if the targeted system for the technology is green power and charging control for vehicles, which needs high voltage and high power tolerance far more than it needs speed and density.

By: Tektrix

Tektrix — Mon, 14 Dec 2009 22:24:00 +0000

@emc2

Gallium is extracted from bauxite. (see, Mikolajczak, C, Availability of Indium and Gallium, Sept. 2009 http://www.indium.com/_dynamo/download.php?docid=552). Gallium is present in bauxite at around 50 ppm (http://www.mii.org/Minerals/photogallium.html). The reserves of bauxite are huge at ~27,000,000,000 metric tones (http://en.wikipedia.org/wiki/Bauxite). Currently, only about 10% of the available gallium is extracted from bauxite. Would seem there is a lot of it available.

By: Ed Korczynski

Ed Korczynski — Mon, 14 Dec 2009 21:39:09 +0000

GaN has been studied for many years, and is currently the semiconductor crystal that creates blue LEDs. Nitronex sells GaN on silicon wafers for HEMT and LDMOS apps. Like all compound semiconductors, GaN single-crystals are more difficult and expensive to work with compared to silicon, and so will be limited in use to niche applications such as discrete power amplifiers, LEDs, and money-is-no-object military/aerospace ICs (the few applications where Si cannot get the job done). As a comparison, recall that GaAs ICs remain niche chips after 25 years of work, though Skyworks and others have made nice businesses out of expoiting such niches.

By: emc2

emc2 — Fri, 11 Dec 2009 16:06:42 +0000

Go Navy. You have to wonder, if it is this useful, whether there will be enough of it (gallium nitride)

By: Andy

Andy — Fri, 11 Dec 2009 15:32:38 +0000

@Marco: a patent only gives the patent holder the right to prevent others from practicing the invention. The patent holder may choose not to exercise that right, may grant a license for no cost, or may charge a licensing fee. Assuming they charge a fee, a reasonable expectation, history has shown that this is not an impediment to further R&D. The semicon industry is crowded with patents on every aspect of process technology and device architecture, and I haven’t noticed any letup in the pace of development. Cross-licensing arrangements are commonplace, and are built into the economics of R&D.

By: Marco

Marco — Thu, 10 Dec 2009 19:53:04 +0000

I’m confused, how is patenting this going to make the design be adopted faster if it really is the replacement for silicon and the future of electrical devices?