Ballistic deflection transistor

Ballistic deflection transistors (BDTs) are electronic devices, developed since 2006,<ref>Template:Cite book</ref> for high-speed integrated circuits, which is a set of circuits bounded on semiconductor material. They use electromagnetic forces instead of a logic gate, a device used to perform solely on specified inputs, to switch the forces of electrons. The unique design of this transistor includes individual electrons bouncing from wedge-shaped obstacles called deflectors.<ref name=Sherwood2006>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Initially accelerated by electric field, electrons are then guided on their respective paths by electromagnetic deflection. Electrons are therefore able to travel without being scattered by atoms or defects, thus resulting in improved speed and reduced power consumption.<ref name=Bell1986>Template:Cite journal</ref>

Purpose

A ballistic deflection transistor would be significant in acting as both a linear amplifier and a switch for current flow on electronic devices, which could be used to maintain digital logic and memory. A transistor switching speed is greatly affected by how fast charge carriers (typically, electrons) can cross from one region to the next. For this reason, researchers want to use ballistic conduction to improve the charge-carrier traveling time.<ref name=Bell1986 /> The conventional MOS transistors also dissipate a lot of heat due inelastic collisions of electrons and must switch fast in order to reduce time intervals when the heat is generated, reducing their utility in linear circuits.<ref name=Sherwood2006 />

Advantages

One advantage of the ballistic deflection transistor is that because such device will use very little power (implementing adiabatic circuit), it will produce less heat, and therefore be able to operate faster or with higher duty cycle. Thus, it will be easier to utilize in the variety of applications. This design will also reduce electrical noise that come from the electronic devices.<ref name=Sherwood2006 /> Along with an increased speed, another advantage of the ballistic deflection transistor is that it will be usable in both aspects of linear amplifier and switch.<ref name=Bell1986 /> Additionally, the ballistic deflection transistors are intrinsically small, because only small size allows to reduce the role of mechanisms responsible for inelastic scattering of electrons, normally dominating larger devices.<ref name=Natori1994>Template:Cite journal</ref>

Alternative approaches to ballistic conduction

The goal of many laboratories around the world is creating switches and amplifiers that can operate faster than current technology.<ref name=Bell1986 /> Specifically, electrons within the device should demonstrate a ballistic conduction behavior.<ref name=DyakonovShur1993>Template:Cite journal</ref> Currently, the silicon MOS field-effect transistor (MOSFET) is the main and leading circuit. However, researchers predict that finding the ideal semiconductor will decrease the dimensions of the transistor, even below the sizes observed in the current generation of the silicon transistors, resulting in many undesirable effects lowering the performance of the MOS transistors.<ref name=Bell1986 /> Since early 1960s, there has been research aiming for the ballistic conduction, which lead to modern metal-insulator-metal diodes, but it failed to produce a three-terminal switch.<ref name=Bell1986 /> Another approach to ballistic conduction was to reduce scattering by lowering temperature, resulting in superconducting computing.<ref name=Natori1994 /> The ballistic deflection transistor comprise the recent (in 2006) design been created by the Cornell Nanofabrication Facility, using a two-dimensional electron gas as the conducting medium.<ref name=Sherwood2006 />

An earlier vacuum-tube device called a beam deflection tube provided a similar functionality based on a similar principle.