Despite all the evidence for three dimensions, big chunks of the world like to stay two dimensional. I could be talking about how much most 3-D movies suck, but I wasn't actually. I was thinking more about computer chips. It turns out to be pretty hard to fully exploit all three dimensions in the design of integrated circuits, and as a result most designs have just a few layers.
The human brain is also area intensive - the notoriously wrinkled and crinkled shape is evolution's way of packing more surface area into a reasonable volume. I'm not sure what the biological reasons are restricting more three dimensional designs, but in the case of computer chips, it's heat dissipation and design complexity that rule.
Katherine Bourzac, writing in Technology Review, has the story on the latest attempts to take chips 3-D.
IBM will work with materials manufacturer 3M to develop the necessary mortar to build much more complex three-dimensional computer chips. The companies announced this week that they will aim to develop microchips made of 100 chip layers stacked on top of each other. Stacking chips in this way could make all sorts of electronics faster and more power-efficient.
Three-dimensional chips have already found their way into some niche applications, but they are expensive to make, and can only be stacked about a dozen layers high before they overheat.
Three-dimensional chips can handle data more efficiently because data has to travel less distance to reach a different component. Stacked chips with connections running through them vertically like pipes in a skyscraper should be able to process more data faster, and with lower power requirements.
The key ingredient needed: a material with mechanical strength that is an excellent heat conductor and an excellent electrical insulator to separate the layers. For the most part, these properties don't like to live together - the article doesn't really tell how well the search is going.