Design and simulation of double-lightly doped MOSCNT using non-equilibrium Green's function

作者：Moghadam Narjes; Aziziyan Mohammad Reza; Fathi Davood^*

来源：Applied Physics A-Materials Science & Processing, 2012, 108(3): 551-557.

DOI：10.1007/s00339-012-6926-2

In this paper, we propose a new ohmic-structure of ballistic carbon nanotube field-effect transistors (CNTFETs) in which the source and drain regions are doped stepwise and the device acts as MOSFET like CNTFET (MOSCNT). The number of lightly doped regions and their doping concentrations are optimized to obtain the lowest OFF current. To study the device characteristics, the Poisson-Schrodinger equations are solved self-consistently using the Nonequilibrium Green's NEGF) formalism in the mode space approach. To find the Hamiltonian matrix, the tight-binding approximation with only p (z) orbital is used. The obtained results show that the stepwise regions lead to barrier widening due to the reduction in potential gradient. Therefore, the band-to-band tunneling (BTBT) and the ambipolar behavior of the device decrease due to band engineering. This causes to the superior reduction of OFF current and dissipative power. In addition, the device performance shows lower subthreshold swing (SS), smaller drain induced barrier lowering (DIBL), and larger current ratio than that of the previous structures.

• 出版日期2012-9