Atomic layer deposition of HfO2 using HfCp(NMe2)3 and O2 plasma

Abstract

HfO2 thin films were prepared by plasma-enhanced atomic layer deposition using a cyclopentadienyl-alkylamido precursor [HfCp(NMe2)3, HyALD™] and an O2 plasma over a temperature range of 150–400 °C at a growth per cycle around 1.1 Å/cycle. The high purity of the films was demonstrated by x-ray photoelectron spectroscopy and elastic recoil detection analyses which revealed that by increasing the deposition temperature from 200 to 400 °C, the atomic concentrations of residual carbon and hydrogen reduced from 1.0 to <0.5 at. % and 3.4 to 0.8 at. %, respectively. Moreover, Rutherford backscattering spectroscopy studies showed an improvement in stoichiometry of HfO2 thin films with the increase in deposition temperature, resulting in Hf/O ratio close to ∼0.5 at 400 °C. Furthermore, grazing incidence x-ray diffraction measurements detected a transition from amorphous at the deposition temperature of 300 °C to fully polycrystalline films at 400 °C, consisting of a mixture of monoclinic, tetragonal, and cubic phases. Finally, the surface morphology and conformality of HfO2 thin films studied by atomic force microscopy and transmission electron microscopy are also reported.

Reversible nonvolatile and threshold switching characteristics in Cu/high-k/Si devices

“…Al 2 O 3 due to its polycrystalline nature with more grain boundary defects which leads to easier migration of Cu ions. Different previous reports already have confirmed that crystallization is favorable in case of HfO 2 , compared to Al 2 O 3 for direct deposition on Si[33,34,35,36].…”

Characteristics of ALD‐ZnO Thin Film Transistor Using H2O and H2O2 as Oxygen Sources

“…ii) Impurity incorporation caused by a higher growth rate may reduce thin film density. [25] Furthermore, it has been reported that the impurity concentration of low temperature ALD thin films is often higher than that of higher temperature ALD thin films. [26] Therefore, while the growth rate of H 2 O-ZnO deposited at 250 °C is higher than that of H 2 O 2 -ZnO deposited at 100 °C, the former has a higher density.…”

Thickness and Morphology Dependent Electrical Properties of ALD‐Synthesized MoS2FETs

“…The PMMA was then completely removed by soaking the samples again into acetone. Finally, the fabricated devices were capped with 5/25 nm of thermal ALD AlO x [75] /PE-ALD HfO x , [76] grown at 100 °C (in the FlexAl reactor).…”