The Effects of Thickness of Source/Drain Fin on <I>P</I>-Channel FinFET Devices and the Corresponding Quantum Effects

Abstract

FinFET devices are considered to be the potential ones replacing the traditional CMOSFET in the sub-nanometer regime. The 3-D structural fins depress the leakage current from being outrageously out of control as the sizes of devices get substantially shrunk. In this study, the fin-thickness effects on the electrical performances are mainly observed. Three different kinds of thickness (namely, 0.110 m, 0.115 m, and 0.120 m) with the same channel length (0.1 m) are put into comparison. The phosphorus implants of the same dose with different energies for N-well threshold voltage adjustment are also taken into account. The threshold voltage, swing, and the mobility are to be determined.

Conclusive Algorithm with Kink Effects for Fitting 3-D FinFET and Planar MOSFET Characteristic Curves

“…Moreover, the threshold voltages (Vth) vary at various VGS not only for FinFET but also for MOSFET, where Vtho may be written as follows: where "FB" means flat-band voltage, Qox is the charge located in the oxide layer, Cox' is the unit capacitance, Qdep is the space charge in the depletion region, and 2|| is the basic applied VGS that causes the strongly inversed layer for Vtho. Somehow, the Equation ( 3) is rewritten as the following fitting formula: 4), f(VGS)=(1-VGS) is defined to deliberately set the condition of VGS under 1.0 V. [22] In the fitting presented in Figure 6a and 6b, =0.085 and =0.1 correspond to p=4.4×10 23 (1/m 3 ) and p=1.6163×10 22 (1/m 3 ), which help identify the thickness of strongly inversed layer to be 182 angstrom at VGS_FinFET=1.0V and 92 angstrom at VGS_MOSFET=0.4V, as referred in Figure 6c.…”

An alternative algorithm to demonstrate electrical characteristics of N/P-channel Fin-FET devices

“…Nevertheless, one may speculate that it might have been unavoidably under the regime of quantum effects [8]. In one-dimensional approximations, carriers shall travel in between the two walls causing the extra heat [9,10] or thermal noise in the channel. On the other hand, the carriers under strong inversion require no trespassing energy over the central barrier and conduct Source and Drain.…”

The alternative algorithm for the determination of threshold voltages on N-channel Fin-FET devices

“…As the scale of the devices shrinks, more attentions must be paid to the quantum effects [8] and their corresponding influences on the electrical characteristics. As the potential well in the fin has been built, the carriers with energy exceeding the center of the potential well may bounce back and forth in between the two walls, causing the extra heat [9,10] or thermal noise in the channel. On the other hand, the bound states nearby the oxide proceed to conduct the current as the device is strongly inversed as shown in Fig.3( C ).…”