Electrical characterization of n-type cylindrical gate all around nanowire junctionless transistor with sio2 and high-k dielectrics

Abstract

In this work, the electrical characteristics of n-type cylindrical gate all around (GAA) nanowire junctionless transistors (NWJLT) of different gate oxides are investigated and analyzed. Silicon dioxide (SiO2) and two high-k dielectrics which are silicon nitride (Si3N4) and hafnium dioxide (HfO2) were used in this study. GAANWJLT of different gate lengths (LG) and nanowire diameter (dNW) were simulated, compared and analyzed to obtain the most optimum device. SDE and Sdevice tools of Sentaurus TCAD were used to simulate and extract the electrical properties of the proposed devices. It was found that GAANWJLT with high-k dielectrics significantly exhibits better electrical properties than with SiO2 due to increase in internal fringe capacitance of the gate dielectric layer. SCEs were considerably improved as the gate-to-channel capacitance reduced. It was found that, for LG of 7 nm and dNW of 6 nm GAANWJLT, device with HfO2 exhibits better electrical properties with more than 2-fold elevated in ION/IOFF ratio and about 15% improvement in SS than the conventional device with SiO2. It proves that GAANWJLT with HfO2 exhibits the most optimum electrical characteristics among the three devices, hence the best alternative to improve SCEs as well as to increase the switching speed of the transistor devices.