Gallium Arsenide Semiconductors on the Horizon

Masem writes: "According to this Chicago Tribune article, Motorola has developed a cheaper solution for putting gallium arsenide on top of silicon in order to allow for better chip designs with speeds nearly 40 times what silicon only chips would allow. While it was well known that gallium arsenide addition was favorable, it was also very expensive; Motorola's new process (covered by 200+ patents) should keep the chip prices low when these new designs are released in 2 years." The AP says they've applied for 270 patents.

Comments

What great news !

[The_Jazzman]

There are two schools of thought when it comes to computers and the world around us.

One might say that computers and ourselves are becoming too involved with each other, us being dependant on the computers.

The other says that each technological breakthrough is a good thing, advancing us to a greater extent each time.

I subscribe to the latter view.

Taking in this point, cheaper chips are something that we should really be striving to produce. If we could come up with microchips so cheap that they cost fractions of pennies yet had the processing power of, I don't know, an Atari ST (8Mhz IIRC) then think of the places we could put them - and cheaply !

For example, The London Underground 'tube' network in England is currently trialing a new ticketing system whereby rather than having a cardboard ticket with a magnetic stripe down one side, they issue tickets which have so-called 'smart chips' inside them.

The flipside is good for LU - think how much extra effort it would be to forge a ticket.
For the everyday train user it makes life just that bit easier. No more scrabbling around for your ticket, as long as it's somewhere on your person you'll able to walk straight through the ticket barrier without having to even think about it.

III-V in the UK

[Anonymous Coward]

For GaAs (III-V) research in the UK, check out the EPSRC UK central facility webpage at the Electrical Engineering department of Sheffield University.

Sorry Folks.

[clark625]

Nothing to see here. Move along, please.

Okay, this just happens to be the research area I work in--and I know full well the problems associated with getting high quality GaAs on Si. It's not nearly as simple as it sounds. So, it appears that Motorola found a "magical" insulating layer to put between the Si substrate and the GaAs layer. Wonderful. But it won't ever be anything but a novelty.

Here's why: In industry, everything is driven by economic margins. Plus, the pure Si industry is now very mature and they will not simply add new machinery to their processes that screw up their entire production line. That makes sense, really. Why on earth ruin a perfectly great production line just to toy around?

The other great point is final production cost. There is no way the pure Si industry will adopt a single step that is far costlier than the rest of their production line combined. Then add to the fact that those industries are adverse to any step that may slow down their production runs or cause unnecessary problems.

Sorry, people. If you want GaAs on Si, there is only one way that it can be made which will result in something the Si industry is not too adverse to. That means epitaxial growth of any buffering layers followed by high quality GaAs growth. The biggest problem that still hasn't been worked out is how does one go about making proper interconnections? Also, the buffering layer can be very conductive--and that is sometimes very hard to control. Motorola has got their heads up where it doesn't belong if they think the world is going to go crazy over this.

Re:"40 times faster"

[SysKoll]

It's a good question, and the answer is "roughly c/3". But it's not the whole picture.

Signal propagation in chips is not limited just by the speed of light. You have leaks due to line capacitance, which also induces coupling (crosstalk) between adjacent lines. If you send a nice square pulse on a 3-mm long straight metal line crossing half a chip (I've seen it!) you'll get an ugly, slow-rising pulse full of parasites picked by crosstalk on its way. And, oh, it will also bounce so badly that you better be prepared to sustain NEGATIVE voltages.

Want more fun? Get a 500-MHz signal on a metal line, and have the line do a sharp 90-degree turn. Everything then happens as if most electrons you send miss the turn and keep moving on their trajectory as bullets from a railgun. Not only will your signal be badly attenuated, it will also induce a crazy crosstalk in anything near that 90-degree corner.

See why chip designers become crazy? Sometimes you wonder how something as simple as an electron can be such a devious little bastard. :-)

EMP Hardened?

[DaedalusLogic]

I remember from a materials science course that GaAs semiconductors were more resistant to electromagnetic fields' influence... What kind of applications could these chips be better for than straight silicon? The military has plenty of applications... but what industries could specifically benefit from cheap electromagnetically "rugged" chips?