Investigating high-k on thin film

Abstract

With the introduction of new materials, to overcome challenges in miniaturization, the silicon process technology works towards further scaling intensively. The research seeks to identify a gate dielectric material in replacement for silicon dioxide (SiO2) and to demonstrate reduced leakage current while driving sufficient current across the transistor channel. A gate insulator has to prevent electrons from tunneling through and permeable enough to allow electric field into the channel, to switch the transistor on. Hence this new proposed material has to be electrically thin and concurrently physically thick. High-k materials (metal oxides such as HfO2, ZrO2 and TiO2) were introduced to evaluate the limitations of SiO2. These prospective candidates were further discussed and elaborated, in relation to the traditional SiO2 dielectric gate structure for the future Complementary Metal-Oxide-Semiconductor (CMOS) technology. Primary basis for the ideal material selection would be through forming ternary compounds by means of doping in HfO2, which would help to improve the thermodynamic stability, increase the dielectric permittivity and raise the crystalline temperature. Three dopants (TiO2, SiO2 and La2O3) had been analyzed in detail and critically evaluating their effectiveness in replacing SiO2 in future applications. HfLaOx has proven to be superior in terms of thermodynamic stability, high crystalline temperature, no degradation of the dielectric permittivity value.