The ultimate switch
Chun-Yung Sung, Ji Hyun Lee · IEEE Spectrum · 2012
From the outside, transistors seem so simple and straightforward. But inside, they're actually a mess. If you could watch them working at the level of atoms, you'd see the electronic equivalent of a game of bumper cars. Electrons moving through even the best transistor channel can't go in straight lines. Instead they're buffeted continually by a host of imperfections and vibrations, which together put a strict limit on speed and generate a lot of heat in the process.