In this chapter, a new type of field-effect transistors is considered with a gate and a channel on a basis of two-dimensional systems of carriers. The key point of the device is that the systems are different. In particular, they are formed in different quantum wells or valleys of the carriers spectrum. Due to this difference, the coherent tunneling is reduced and inelastic tunneling requires additional excitations with significant momentum and energy. This decreases the tunneling rate significantly. For example, the intervalley tunneling rate is less than intravalley that in 9 orders of magnitude in GaAs/AlAs heterostructures. The two-dimensional character also can decrease the tunnel probability in a wide voltage range. Influence of further miniaturization will be discussed for the new types of the transistors.
Part of the book: Different Types of Field-Effect Transistors