Characteristics of the HfO2 Film depositied using TDEAH and Hf(mp)4 by Remote Plasma Enhanced Atomic Layer

Abstract

HfO2 have been extensively investigated as alternatives to SiO2 in the downscaling of metal-oxide semiconductor devices due to its high dielectric constant (25~30), high density (9.68 g/cm3), large bandgap (5.68 eV) and good thermal stability in contact with silicon. For these reasons, we investigated the HfO2gate dielectric material deposited by remote plasma enhanced atomic layer deposition (RPEALD) method. RPEALD method is expected to minimize the impurities of film and damage of substrate, increase the reactivity, widen the process window and improve the film qualities such as density. HfO2 films were deposited using TDEAH containing no oxygen elements and newly synthesized Hf(mp)4 containing oxygen elements as Hf precursor and oxygen plasma as reactant gas, respectively. In this study, plasma diagnostics was carried out by using Langmuir probe method to confirm the remote plasma and plasma density was decreased out of discharge region. We deposited HfO2 films with RPEALD system and thickness of HfO2 was controlled by the number of deposition cycle. After growing HfO2 films, the electrical properties of HfO2of MOS capacitor were measured. The physical and chemical characteristics of HfO2 film were analyzed by cross-sectionaltransmission electron microscope, Auger electron spectroscopy, X-ray photoemission spectroscopy. The electrical properties including EOT, hysteresis, leakage current and capacitance were evaluated by I-V and C-V measurements. This paper presents comparison of the characteristics of the HfO2deposited by RPEALD method using the two different metal organic precursor, TDEAH and Hf(mp)4.