ABSTRACT
The junctionless transistor consists of a piece of uniformly doped semiconductor with a gate placed between the source and drain contacts and is, therefore, the simplest transistor structure. The junctionless transistor is essentially a thin-body, heavily doped semiconductor resistor with a constant uniform doping concentration from source to drain and a gate electrode that controls the flow of current between source and drain. In a junctionless transistor, part of the current is due to purely resistive conduction in the bulk of the device. Junctionless nanowire transistors with a trigate, pi-gate, omega-gate, or gate-all-around (GAA) geometry have excellent subthreshold characteristics. GAA junctionless transistors have been fabricated both in single-crystal and polycrystalline silicon. The junctionless architecture is particularly well suited to the fabrication of vertical GAA nanowire transistors since the gate is automatically self-aligned to source and drain.
