Quantum simulation study of gate-all-around (GAA) silicon nanowire transistor and double gate metal oxide semiconductor field effect transistor (DG MOSFET)

Abstract

In this paper, electrical characteristics of the double gate metal oxide semiconductor field effect transistor (DG MOSFET) and that of gate all around silicon nanowire transistor (GAA SNWT) have been investigated. We have evaluated the variations of the threshold voltage, the subthreshold slope, draininduced barrier lowering, ON and OFF state currents when channel length decreases. Quantum mechanical transport approach based on non-equilibrium Green's function method (NEGF) has been performed in the frame work of effective mass theory with taking into account exchange-correlation effects. Its simulation consists of solutions of the three dimensional Poisson's equation, two dimensional Schrodinger equation on the cross section plane, and also transport equation. We have shown that for lengths smaller than 15 nm, short channel effects dominate. When the dimensions become smaller, interelectronic distance decreases and the interaction between electrons and also exchange correlation effects increase. We have also demonstrated that short channel effects are decreased using the device which has a good control of gate.

Comparative analysis of gate-oxide engineering in charge plasma based nanowire transistor

“…Moreover, due to the shrinking of the device size to the sub-10 nm range, the classical drift-diffusion models are insufficient to characterize the electrical properties, and complete quantum transport models should be applied for accurate prediction of the device characteristics. The sub-10 nm node and reduced nanowire diameter necessitate consideration of the full quantum transport equation, which will include ballistic conduction, direct source-to-drain tunneling, and the quantum confinement effects [22]. In the absence of comprehensive analysis on charge plasma-based nanowire MOSFETs including quantum transport in the literature, we investigated the effects of three different gate oxide formations of charge plasma-based nanowire transistor (CPNWT) in terms of SCEs parameters such as I on , I off , subthreshold voltage (V th ), and DIBL incorporating the non-equilibrium green gunction (NEGF) method.…”

Nanowire gate-all-around MOSFETs modeling: ballistic transport incorporating the source-to-drain tunneling

“…Owing to their excellent gate controllability over the channel, [1][2][3][4] gate-all-around (GAA) metal-oxide-semiconductor field-effect transistors (MOSFETs) have been considered as one of the most promising candidates for the future CMOS generation. [5][6][7][8][9] Although the dimensions of semiconductor devices aggressively shrink down, these devices can still provide a better immunity to short channel effects, such as threshold voltage roll-off and drain-induced barrier lowering (DIBL). 3,5,10,11) As the channel length of MOSFET is projected to reach sub-7 nm regime in recent years, 12,13) it is widely investigated that quantum transport of electrons should be taken into account when describing the device properties.…”

“…14,15) In addition, the source-to-drain direct tunneling within MOSFETs in the subthreshold region is broadly recognized to play a role in the undesirable degradation of the subthreshold parameters. 8,[16][17][18] Since the ballistic characteristics are also significantly demonstrated in the ultrashort-channel devices, [19][20][21] it becomes increasingly necessary to develop a compact model for the cylindrical ballistic GAA MOSFET including both the source-to-drain tunneling and thermionic transport.…”

“…The electron behavior involving ballistic transport and quantum mechanical effect in GAA MOSFETs can be accurately simulated and computed in several numerical simulators by using non-equilibrium Greenʼs function (NEGF) formalism. 8,[22][23][24] However, since it requires a enormous amount of time for such simulations in calculating the device characteristics, the computations are not suitable to be used in a system-level circuit simulation. Several analytical compact models of short-channel ballistic GAA MOSFETs have been put to use so far, [25][26][27] who can perfectly describe the current characteristics while the source-to-drain tunneling in such MOSFETs can be negligible.…”