Impact of Channel Surface Orientation on the Electrical Characteristics of Ultra-Thin Body DG MOSFETs

Abstract

The trend of size shrinking is no longer as straightforward as traditional Moore's Law in the past How to improve the electrical characteristics of transistors is still highly considered as a major target of today's investigation The structural evolution planar MOSFETs fin-FET and gate-all-around MOSFET it to improve the gate electrostatic control of the nanoscale complementary metal-oxide-semiconductor (CMOS) Also the impact of the material properties of the device as band structure crystal orientation quantum confinement effect and carrier mobility is an essential topic in the direction of research This thesis intends to investigate the impact of crystal surface orientation on the band structure of the ultra-thin body (UTB) and the electrical characteristics of a MOSFET based on the UTB First we introduce the empirical tight-binding (ETB) theory for the bulk material Then we generalize the ETB model to a material with the UTB structure where has one direction confined in a nanoscale thickness in a specified crystal direction Based on the ETB calculated band structure we obtain several material parameters such as electron effective masses and band offset at different valleys and spatial directions which are essential for quantum transport simulations Apply the obtained quantum parameters to the device structure With non-equilibrium Green's function (NEGF) method and quantum ballistic transmission assumption we simulate the electrical characteristics of double-gate (DG) MOSFETs based on the UTB Finally we analyze and compare the impact of the crystal surface orientation of the channel material in the same channel direction on the electrical characteristics of the devices

Date of Award	2019
Original language	English
Supervisor	Kuo-Hsing Kao (Supervisor)