Engineers at IBM Research have built the world’s most advanced graphene-based chip, with performance that’s 10,000 times better than previous graphene ICs. The key to the breakthrough is a new manufacturing technique that allows the graphene to be deposited on the chip without it being damaged (something that has heretofore been very hard to achieve). Perhaps more importantly, though, this new method is actually compatible with standard silicon CMOS processes. In short, we are closer than ever before to realizing a commercial graphene computer chip.
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In case you were wondering, the graphene is grown in a furnace. A copper foil is placed in a furnace at 1,050C (1,922F) with an atmosphere of methane, resulting in a single layer of graphene being deposited on the foil. The copper is dissolved away in a bath, leaving a layer of graphene floating there. The silicon wafer, with all the passive components already in place, is then used to “scoop up” the graphene layer out of the bath. (Bear in mind that the graphene is transparent, too.) This is currently the easiest way to grow large amounts of graphene, but the IBM engineers told me that the quality of graphene grown in this way isn’t great, and that having to destroy the copper substrate is expensive and inefficient.
Moving forward, it’s important to note that we’re still very much talking about an analog chip. IBM Research still hasn’t found a way of giving graphene the all-important bandgap that is required for the fabrication of digital logic, and thus graphene-based computer processors. For next-gen processors, IBM seems to be focused on carbon nanotubes, which can have a band gap, over graphene. (More on that later, when I write up my trip to IBM Research.) Assuming we can one day create large quantities of high-quality graphene, though, there are plenty of radio and optical applications that could benefit — in theory, graphene is capable of operating at frequencies as high as 500GHz, well beyond any other material currently used in RF applications.
