Comparison of tunnel currents through SiO<inf>2</inf>, HfO<inf>2</inf>, Ta<inf>2</inf>O<inf>5</inf>, ZrO<inf>2</inf> and Dy<inf>2</inf>O<inf>3</inf> dielectrics in MOS devices for ultra large scale integration using first principle calculations

Abstract

The work presented in this paper focuses on the effects of high leakage current in field effect transistors and the possible ways to play down with the leakage currents. This paper combines density functional theory and non equilibrium Green's function formalism to perform atomic scale calculation of tunnel currents through SiO 2, HfO 2 , Ta 2 O 5, ZrO 2 and Dy 2 O 3 dielectrics in MOSFETs. The tunnel currents for different bias voltages applied to Si/Insulator/Si systems have been obtained along with tunnel conductance v/s bias voltage plots for each system and the plots have been analyzed with reference to the presently used bulk Si/SiO 2 /Si systems that have SiO 2 as the gate dielectric material. The results justify the use of high dielectric constant materials as gate dielectric in FET devices so as to enable further downscaling of MOSFETs with reduced gate leakage currents thereby enabling ultra large scale integration.

Co-60 GAMMA RADIATION INFLUENCES ON THE ELECTROCHEMICAL, PHYSICAL AND ELECTRICAL CHARACTERISTICS OF RARE-EARTH DYSPROSIUM OXIDE (Dy 2 O 3 )

“…As a possible replacement for gate dielectrics, Dy2O3 is one of the most promising REO materials owing to its high dielectric constant (k = 14-18), a large energy band gap (4.9 eV), and thermal and chemical stability with silicon [14]- [16]. Researchers have already reported that Dy2O3 exhibits promising performance in gate dielectric applications [5], [17], [18]. However, together with these initial studies, the stability of the device should be investigated in various environments including the irradiation field to test the device reliability.…”