Real estate and Silicon have a common limitation: space is finite. So the more apartments—or semiconductor components—you can pile on top of one another on a single block, the greater the cost savings. That's the idea behind the 3D chip technology from Matrix Semiconductor.

Standard integrated circuits put all the active circuitry on the silicon substrate and then add layers for the connecting wiring and insulators. Matrix's 3D design actually piles multiple layers of active memory elements on a standard silicon substrate so that active circuitry extends horizontally and vertically. What's also different about Matrix's approach is that it isn't trying to build faster, cutting-edge chips. It's trying to save money.

"Silicon real estate is very expensive, and what people have been doing is building ranch houses," explains Dan Steere, vice president of marketing at Matrix. "We save money by reducing the die size and using existing fab plants and technology in new ways."

Matrix's first 64MB memory chips are priced at about $9 a unit versus about $15 for similar flash memory products. The first Matrix memory chips are being used in the Mattel Juice Box, a portable multimedia player aimed at "tweens."

One disadvantage of Matrix's current 3D-memory architecture is that the chips are write-once, nonvolatile RAM. So are Nintendo game cartridges, though, and 75 million sold last year. Matrix hopes to extend its 3D technology to many different types of semiconductors.