Gate-controlled quantum collimation in nanocolumn resonant tunneling transistors

Abstract

Nanoscaled resonant tunneling transistors (RTT) based on MBE-grown GaAs/AlAs double-barrier quantum well (DBQW) structures have been fabricated by a top-down approach using electron-beam lithographic definition of the vertical nanocolumns. In the preparation process, a reproducible mask alignment accuracy of below 10 nm has been achieved and the all-around metal gate at the level of the DBQW structure has been positioned at a distance of about 20 nm relative to the semiconductor nanocolumn. Due to the specific doping profile n++/i/n++ along the transistor nanocolumn, a particular confining potential is established for devices with diameters smaller than 70 nm, which causes a collimation effect of the propagating electrons. Under these conditions, room temperature optimum performance of the nano-RTTs is achieved with peak-to-valley current ratios above 2 and a peak current swing factor of about 6 for gate voltages between -6 and +6 V. These values indicate that our nano-RTTs can be successfully used in low power fast nanoelectronic circuits.

A novel self consistent calculation approach for the capacitance‐voltage characteristics of semiconductor quantum wire transistors based on a split‐gate configuration

“…Also, the numerical formulation is not restricted to a specific device geometry and we believe that it can be a useful general purpose tool to optimize the performance of quantum wire devices, by providing useful design guidelines. Work is in progress to apply our model to novel devices, recently demonstrated experimentally (Wensorra et al , 2009).…”

“…For example, in 2005, Yang et al (2006Yang et al ( , 2009 investigated manufacturability issues of split-gate structures for the creation of quantum devices, such as quantum point contacts, quantum wires, quantum dots (Figure 1(d)). Very recently, Wensorra et al (2009), reported a nanocolumn resonant tunneling transistor in which a electrostatic field around the nanocolumn induces a quantum collimation effect to improve the resonance characteristics, including peak-to-valley ratio.…”

Aspectos de modelagem numérica de transistores de fios quânticos

“…Micrografias SEM do RTT de nanocoluna: b) vista de fora e c) vista de cima. Micrografias e esquemas retirados do trabalho de Wensorra, Ref [27]…”