Analysis of Quantum Effects on Backscattering from Drain Region of Double-Gate Metal–Oxide–Semiconductor Field-Effect Transistor

Abstract

We have analyzed quantum effects on backscattering from the drain region of a silicon decanano double-gate metal-oxide-semiconductor field-effect transistor (DG-MOSFET) using a Monte Carlo simulation. A backscattered (BS) rate with a full quantum effect is larger than that in the classical case. To investigate the causes, we have separated the full quantum effect into a subband energy effect and a twodimensional electron gas (2DEG) transport effect. It is confirmed that the main cause of the increase in BS rate caused by the full quantum effect is the 2DEG transport effect. The 2DEG transport effect causes an electron distribution concentration on the center of the channel thickness, an increase in scattering rate at the drain edge and in the channel, and a tendency of the BS electrons to diffuse toward the source in the channel. Furthermore, we confirmed that the subband energy effect contributes greatly to the increase in BS rate caused by the full quantum effect in a channel as thin as 2 nm. The subband energy effect causes a strong tendency of the BS electrons to diffuse toward the source in the very thin channel. The contribution to the increase in BS rate of the subband energy effect, in addition to that of the 2DEG transport effect, becomes large when the channel is very thin. #

Study of Backscattering Phenomenon from Drain Region of Silicon Decanano Diode Using Nonequilibrium Green's Function Approach

“…[6][7][8] However, we analyzed the backscattering effect from a drain region of the submicron/decanano devices on the carrier transport characteristics and device characteristics using Monte Carlo simulation. [9][10][11][12][13] It was already found in our previous research that the backscattering from the drain region markedly affects AC device characteristics. When a small incremental change in backscattered ratio, (BS ratio), is increased from 0.35 to 1.15%, the cutoff frequency ( f T ) of the device is degraded from 210 to 160 GHz.…”

“…where the external region is a region outside of the channel such as the source, drain, or electrode. Although this ''BS ratio'' is same as the ''BS rate'' defined in our previous paper, 12,13) we rename it here from ''BS rate'' to ''BS ratio'' to emphasize that it is the ratio of backscattered electrons, because ''BS rate'' causes misunderstanding of the frequency per unit time of backscattering. We analyzed the electron wave transport without scattering in the device using our developed NEGF simulator.…”

Analysis of channel electrons scattered in each region of silicon nanodiode at low drain voltage using nonequilibrium Green’s function approach

“…[6][7][8] However, we have investigated the effect of the backscattering (BS) phenomenon "from the drain region" of submiron/deca-nanodevices on carrier transport characteristics and device performance using Monte Carlo simulation. [9][10][11][12][13] It is desired that the quantum effect be incorporated for the simulation of much smaller deca-nanodevices. Recently, quantum mechanical device simulation using the nonequilibrium Green's function (NEGF) method has been used for ultrasmall devices.…”

Comparative study on nano‐scale III‐V double‐gate MOSFETs with various channel materials

“…However, the simulation studies have showed some challenges in realizing the high current drivability owing to some phenomena such as source starvation [4,5] and electron rebound from drain [6], which have closely been related to the geometry and composition of the channels [5,7]. We have investigated the current drivability of III-V single-gate (SG) MOSFETs with various channel materials and have showed the superiority of the InP channel [8].…”