Nucleation and Growth of Platinum Films on High-k/Metal Gate Materials by Remote Plasma and Thermal ALD

Abstract

Platinum films were grown on Si wafers, SiO2, Al2O3 and high-k dielectric HfO2 ALD films on Si substrates by both remote plasma and thermal atomic layer deposition (ALD) at 300°C, using methylcyclopentadienyl_trimethyl platinum (MeCpPtMe3) and O2 as precursors. The ALD Pt-films deposited were homogeneous and resulted in a low resistivity of 12.8 μΩ-cm. AES studies revealed high quality Pt films deposited by both thermal and plasma ALD with carbon impurity less than 1.5% and oxygen found only in the interface. SEM and EDX were used to investigate Pt nucleation and growth in ALD processes. It is remarkable that the nucleation delay of between thermal and plasma ALD Pt was different though they are a similar growth rate of 0.45 Å/cycle. In this work, the Pt ALD nucleation and growth behaviours with precursor dose times, O2 or O2 plasma exposures and substrates are also investigated.