Characteristics of Metal-Oxide-Semiconductor Field-Effect Transistors with Hfo_2/SiO_2/Si and Hfo_2/SiO_xN_y/Si Stack Structures Formed by Remote Plasma Technique

摘要

Thin SiO_2 and SiO_xN_y layers were grown on Si substrates using remote plasma oxidation and nitridation, respectively, to use as buffer layers prior to HfO_2 deposition. Subsequently, HfO_2 films were grown on these buffer layers by remote plasma atomic layer deposition (RPALD). The SiO_2 and SiO_xN_y buffer layers suppressed the growth of Hf silicate at the interface during HfO_2 deposition, suppressed the increase in total oxide capacitance, and induced the decrease in effective fixed oxide charge density. Metal-oxide-semiconductor field-effect transistors (MOSFETs) with buffer layers exhibited a higher drain current (I_d) and effective carrier mobility (μ_(eff)) than those without buffer layers. The incorporated N atoms in SiO_2 buffer layer reduced both I_d and μ_(eff) of MOSFETs due to the increase of defect charge in the interfacial region, compared to SiO_2 buffer layer including no N atom.