Shin-Nam Hong

Output Characteristics of Carbon-nanotube Field-effect Transistor Dependent on Nanotube Diameter and Oxide Thickness

Carbon-nanotube field-effect transistors (CNFETs) have drawn wide attention as one of the potential substitutes for metal-oxide-semiconductor field-effect transistors (MOSFETs) in the sub-10-nm era. Output characteristics of coaxially gated CNFETs were simulated using FETToy simulator to reveal the dependence of drain current on the nanotube diameter and gate oxide thickness. Nanotube diameter and gate oxide thickness employed in the simulation were 1.5, 3, and 6 nm. Simulation results show that drain current becomes large as the diameter of nanotube increases or insulator thickness decreases, and nanotube diameter affects the drain current more than the insulator thickness. An equation relating drain saturation current with nanotube diameter and insulator thickness is also proposed.

Property Comparison of Ru-Zr Alloy Metal Gate Electrode on ZrO 2 and SiO 2

In this dissertation, Ru-Zr metal gate electrode deposited on two kinds of dielectric were formed for MOS capacitor. Sample co-sputtering method was used as a alloy deposition method. Various atomic composition was achieved when metal film was deposited by controlling sputtering power. To study the characteristics of metal gate electrode, C-V(capacitance-voltage) and I-V(current-voltage) measurements were performed. Work function and equivalent oxide thickness were extracted from C-V curves by using NCSU(North Carolina State University) quantum model. After the annealing at various temperature, thermal/chemical stability was verified by measuring the variation of effective oxide thickness and work function. This dissertation verified that Ru-Zr gate electrodes deposited on have compatible work functions for NMOS at the specified atomic composition and this metal alloys are thermally stable. Ru-Zr metal gate electrode deposited on exhibit low sheet resistance and this values were varied with temperature. Metal alloy deposited on two kinds of dielectric proposed in this dissertation will be used in company with high-k dielectric replacing polysilicon and will lead improvement of CMOS properties.

Characteristics of Mo Gate Electrode Deposited on ZrO 2 Gate Insulator

In this work, MOS capacitors were used to study the electrical properties of Mo gate electrode deposited on ZrO. The workfunctions of Mo gate extracted from C-V curves were appropriate for PMOS. Thermal stability of Mo metal was investigated by analyzing the variations of workfunction and EOT(effective oxide thickness) after 600, 700, and 800 RTA(rapid thermal annealing). It was found that Mo gate was stable up to 800 with underlying ZrO. The resistivities of Mo were 35Ωcm∼ 75Ωcm. These values are lower than those of heavily doped polysilicon. Based on these measurements, it can be concluded that Mo metal gate with ZrO gate insulator is an excellent gate material for PMOS.

Analysis of PMOS Capacitor with Thermally Robust Molybdenium Gate

In this paper, we report the properties of Mo metal employed as PMOS gate electrode. Mo on was observed to be stable up to by analyzing the Interface with XRD. C-V measurement was performed on the fabricated MOS capacitor with Mo Bate on . The stability of EOT and work-function was verified by comparing the C-V curves measured before and after annealing at 600, 700, 800, and . C-V hysteresis curve was performed to identify the effect of fired charge. Gate-injection and substrate-injection of carrier were performed to study the characteristics of and interface. Sheet resistance of Mo metal gate obtained from 4-point probe was less than that was much lower than that of polysilicon.

Properties of Ru 1 Zr 1 Alloy Gate Electrode for NMOS Devices

This paper describes the characteristics of Ru-Zr alloy gate electrodes deposited by co-sputtering. The various atomic composition was made possible by controlling sputtering power of Ru and Zr. Thermal stability was examined through 600 and 700 RTA annealing. Variation of oxide thickness and X-ray diffraction(XRD) pattern after annealing were employed to determine the reaction at interface. Low and relatively stable sheet resistances were observed for Ru-Zr alloy after annealing. Electrical properties of alloy film were measured from MOS capacitor and specific atomic composition of Zr and Ru was found to yield compatible work function for nMOS. Ru-Zr alloy was stable up to while maintaining appropriate work function and oxide thickness.