Chipmakers have already stopped thinning one key transistor component—the gate oxide. This layer electrically separates the gate, which turns a transistor on and off, from the current-carrying channel. Make this oxide thinner and you can induce more charge in the channel, boost the current, and make the transistor faster. But you can’t reduce the oxide thickness to much less than roughly a nanometer, which is about where it is today. Beyond that, too much current will flow across the channel when the transistor is “off,” when ideally no current should flow at all. And that’s just one of several leakage points.