The device is called a “ballistic deflection transistor,” and it allows electrons to flow in a straight line without having to make the 3D hops up and down through layers of semiconductor material as they do today. This would decrease the number of electrons required to “fire” a transistor and switch it from 0 to 1, which means it would be much, much faster.
HP pursued a similar technology years ago but abandoned that research because it had to operate at very cold temperatures. The UofR researchers believe they have solved that problem and can operate the circuit at room temperature.
The use of silicon was completely abandoned for their research because of the nature of the circuit. This deflection circuit uses a type of triangle to help steer the electrons along and requires a large “mean free path,” which is something scientists call the amount of space an electron can flow in before it hits something in its substrate. For silicon this was only about 10 nm, making it too small to be useful; so, the URochester researchers turned to Indium-Gallium Arsenide and Indium Phosphide for substrate material, which has a mean free path that is 22x as long, at about 220 nm. This allows circuits to be constructed that are small enough (around 70 nm, it seems) without anything else to “bump into” while the electrons are flowing through.
The researchers admit that this theory they've come up with is a long way from a 3THz CPU, but it seems to be the closest we've come to having a reason to leave silicon behind: a room temperature circuit that yields transistor speeds that are at least an order of magnitude faster than their closest silicon cousins, and even those operating on incredibly small feature sizes with specialized cooling. It could be a new big very small thing.
Read more at Technology Review, and post your thoughts below. A 3.0THz transistor … now that's fast.
USER COMMENTS 18 comment(s)
|I for one hope that Alontech gets this. (9:45am EST Tue Aug 29 2006)
Who is Alonatech you say? Why my own company of course. – by Eric the Red
|just a concept like time travel (9:59am EST Tue Aug 29 2006)
ok? – by YuriHA from México
|Rochester… (10:27am EST Tue Aug 29 2006)
Wow there's a lot of recent new “discoveries” or “contributions” at Rochester Institute of Technology (where I attend) and University of Rochester!!! – by Ahhhhh….
|Wait a sec… (11:18am EST Tue Aug 29 2006)
“3D hops”? Maybe in a BJT, but the vast majority of transistors in modern devices are MOSFETs, in which the current takes a perfectly linear path. In these ballistic deflection transistors the electrons do not take perfectly linear paths. They take curvilinear paths within a plane. How is that better than a linear path? I doubt that it is.
Also, this technology review article was poorly written/researched, and therefore misleading. It's true that older, slower technologies such as NMOS use capacitors for maintaining output states, those are rarely used in modern processors because we have the space to use CMOS designs and the delays (and VTCs) of NMOS circuits are inadvantageous. In CMOS, there is no explicit ouput capacitor.
On the other hand, what the article may have intended to point out is that FETs have inherent parasitic capacitances that cause leakage and switching delays. These BDTs will not suffer as much in that respect.
But then on the other hand, you will still need complementary BDTs, or CBDT if you will, in order to make an effective circuit (BDTs suffer the same problem as BJTs and FETs in terms of weak pulls towards one potential level or the other). And BDTs will take significantly more surface area than FETs, so it is likely that the transistor densities will not be favorable.
It is good to see research money pouring into potential future tech like this. FETs won't scale forever.
– by DrSengir
|Yeah but……….. (12:58pm EST Tue Aug 29 2006)
Can it run Solitaire? – by I Doubt It
|pfffft ! meh! (1:44pm EST Tue Aug 29 2006)
it can't beat the PS3. PS3 is human cell! it fast! – by PS fanboy
|Cool (4:31pm EST Tue Aug 29 2006)
How much power does it consume and will it still play doom3 if the made a 3THz processor?
Alright no flames. – by Regulas
|One problem (6:57pm EST Tue Aug 29 2006)
How will we know if it is actually running that fast? Cause there is nothing that can test those speeds that I am aware of. – by IP Student
|yeah (7:07pm EST Tue Aug 29 2006)
the microwave is faster than that! – by fast noise
|My guess (9:14pm EST Tue Aug 29 2006)
This technology is 15 years away.
My Grandkids will love it! – by woot
|My guess (10:42pm EST Tue Aug 29 2006)
in 15 years, this will be 15 years away.
and in another 15 years, it'll be 15 years away.
kinda like fusion power, it's aways been just 30 years ahead of us. – by Pippen
|Give it time (2:42am EST Wed Aug 30 2006)
and the Cell CPU will do this easily in less time then 15 years. Probably when Sony releases the PS4. I am assuming Sony will also solve power concerns by then also. – by GodofWar
|DrSengir (5:14am EST Wed Aug 30 2006)
3D hops refers to the multi-layer construction of modern day semiconductor circuits.
– by RickGeek
|3D Hops (7:35am EST Wed Aug 30 2006)
is't that where you where red and blue glasses and stand on one leg?
All this techno stuff gives me a headache :( – by hophop
|Re: IP Student (8:27am EST Wed Aug 30 2006)
There are many ways one could test if the transistors are working at those speeds. Why not make a counter out of them, calculate the theoretical counting rate based on the theoretical switching speed of the transistors making up the counter, and let it run for a nanosec or so, then read off the value, multiply by 10^9 and voila you have a pretty close approximation of the switching speed. I'm sure there are more accurate ways, but making a counter is a very crude and simple way that anyone could think to do, it doesn't take deep science to test these things.
– by DrSengir
|Re: Pippen (8:31am EST Wed Aug 30 2006)
Nuclear fusion is a completely different animal, which is why it always seems to be 15 years away. The real reason that we haven't developed fusion plants is lack of funding, because in order to get a stable reaction with a net positive power flow you need an enormous reactor, in theory, but no one's really been able to experiment and test such theories because, surprise surprise, no one's willing to fun the multi-billion dollar project. Our government would much rather waste $300 bil on a missile defense system that has proven itself completely worthless over the past 30 years of development.
– by DrSengir
|Re: Rick (8:42am EST Wed Aug 30 2006)
I know what it was referring to, and I'm saying that it is downright incorrect. electrons in FETs don't make “hops” within the FET. Sure the leads for the FET are layered atop the actual FET structure, which does require the electrons to “hop” in the Z direction, but the BDT doesn't address this issue in the least. It is still a printed semiconductor, and as such still requires layers of wire, and electron “hopping” out of plane. On top of that the BDT is larger than a FET and redirects electrons within the plane, whereas FETs do not.
The real advantage to BDTs is that they can switch so quickly, and the most impressive/interesting/useful characteristic of BDTs is that they maintain a constant current throughout operation, which substantially reduces noise and power drain issues. Their fast switching times are due to the fact that they do not have a significant intrinsic output capacitance as FETs do, and because the constant current will reduce noise and power spiking, both of which tend to require longer rise and holding times in modern circuits.
– by DrSengir
|to IP Student (12:44pm EST Wed Aug 30 2006)
You can also use interferometry to figure the frequency. – by Unix Daemon