High-Performance Monolithic Graphene Transistors Created

MrSeb writes "Hardly a day goes by without a top-level research group announcing some kind of graphene-related breakthrough, but this one's a biggy: Researchers at the University of Erlangen-Nuremberg, Germany have created high-performance monolithic graphene transistors using a simple lithographic etching process. This could be the missing step that finally paves the way to post-silicon electronics. In theory, according to early demos from the likes of IBM and UCLA, graphene transistors should be capable of switching at speeds between 100GHz and a few terahertz. The problem is, graphene doesn't have a bandgap — it isn't a natural semiconductor, like silicon — and so it is proving very hard to build transistors out of the stuff. Until now! The researchers say that current performance "corresponds well with textbook predictions for the cutoff frequency of a metal-semiconductor field-effect transistor," but they also point out that very simple changes could increase performance 'by a factor of ~30.'"

Comments

Re:Something missing in the explanation

[sheepe2004]

I read the article (I know it's not considered good form here on Slashdot), and there seems to be a discrepancy: this is described as being a graphene transistor, but the gate uses silicon carbide as the semiconductor. So it seems like a better description would be a hybrid graphene/semiconductor transistor. Is this correct?

If it is a hybrid then what are the limitations and how is it better then current all semiconductor circuits? As far as I know (not very much) there is no reason to build silicon carbide integrated circuits, so why would anyone want to use SIC with graphene? Is this a step to something more useful?

I'm not trolling, I just want to get a better understanding.

Yes. They have only used graphene for the gates and contacts, not the channel itself, so a hybrid graphene/SiC transistor would probably be a better description.

As for advantages over existing technology: as far as I know the switching speed is dependent on the channel material, NOT the gate etc. So these transistors will (afaik) be no faster than a normal SiC transistor. All the hyperbole about graphene transistors being is only in the linked news article and not in the paper. In fact the final conclusion of the paper is:

The concept's particular strength, however, lies in the following property: within the same processing steps, many epitaxial graphene transistors can be connected by graphene strip lines along with graphene resistors and graphene/SiC Schottky diodes, and therefore complex circuits can be built up. As a special feature of graphene in contrast to semiconductors, we anticipate that even a complete logic is feasible.

On the other hand this is still interesting for other reasons:
1) They have demonstrated large scale integration of graphene. If we can get a bandgap in graphene without sacrificing too much mobility then combined with this kind of work we have a complete graphene chip.
2) Another thing they emphasise in the paper is the simplicity of the lithography process. Simpler lithography means it's easier to go smaller. Smaller features = better chips.

TL;DR - the news article is bullshit, the real result is interesting but not revolutionary (yet).