The new vacuum-channel transistor far surpasses its silicon cousin and can save us from Moore’s Law

A new type of transistor is being developed by scientists at the NASA Ames Research Center that meshes together the best aspect of semiconductors and traditional vacuum-tube technology. This Frankenstein device is capable of operating 10 times as fast as traditional silicon transistors without any of the drawbacks of vacuum tubes. The vacuum-channel transistors are in an early prototype stage but have the potential to demolish the impending wall of Moore’s Law.

Unlike traditional vacuum tubes found in older technology, vacuum-channel transistors do not need a filament or hot cathode to heat up in order to emit electrons. Shedding this power-sapping heating element enables the vacuum transistor to be shrunk small enough where the electric field across them remains sufficient enough to draw electronics from the source (using the process of field emission) without suffering from the massive heat generation characteristic of vacuum tubes.

Furthermore, by shrinking the vacuum to nano-metric proportions, the distance between cathode and the anode becomes less than the average distance that an electronic has to travel before colliding with a gas molecule, thereby eliminating the traditional vacuum tube issue of cathode degeneration caused by the constant bombardment of positive ions stemming from the electron-to-gas collision. 
 

Replacing oxygen with helium in the vacuum transistor also increases the mean free path, or distance that a molecule travels between collisions, to one micrometer and further decreases the chance of collisions. Couple this with low voltage, and electrons have no way of ionizing the helium. In other words, the vacuum transistor can function under normal atmospheric conditions — something traditional vacuum tubes cannot do without the risk of electron collision. As a matter of fact, a vacuum isn’t even needed anymore since vacuum transistor is so miniaturized. 

Next, the NASA scientists revolved the issue of controlling the vacuum-channel transistor’s on and off state by controlling current flow in the same manner as it is done in a MOSFET: using an insulating dielectric material to separate the gate electrode from the current channel. The dielectric insulator transfers electric fields where needed and prevents the flow of current into the gate.
 

NASA admits that a great deal of work remains before a commercial product can even be envisioned. Producing a few units in the lab is one thing, but producing and harnessing millions of them into an integrated circuit is another thing altogether. What we do know is that the agency has successfully built working prototypes capable of functioning at 460 GHz, approximately 10 times faster than the best silicon transistor. This frequency would allow vacuum-channel transistors to operate in the terahertz gap, a frequency range between microwave and infrared waves that no conventional semiconductor is quite capable of doing right now.

Via IEEE.Spectrum