in Situ Reaction Mechanism Studies on Lithium Hexadimethyldisilazide and Ozone Atomic Layer Deposition Process for Lithium Silicate

摘要

Reaction mechanisms in the LiN[Si(CH3)3]2—O3 atomic layer deposition (AID) process for lithium silicate were investigated in situ with a quartz crystal microbalance (QCM) and a quadrupole mass spectrometer (QMS) at several temperatures. In addition, ex situ Fourier transform infrared (FT-IR) measurements were carried out to identify the bonds present in the films. QMS indicates typical combustion byproducts such as CO2 (m/z =44), CO (m/z = 28), H2O (m/z = 18) and NO (m/z = 30) during the ozone pulse. Signals corresponding to the fragments of the ligands are present, but their low intensities imply that there are no direct ligand exchange reactions with the hydroxyl groups on the surface. QCM results confirm the decomposition of the ligand through complex reactions upon reaching the surface. Accordingly, several reaction pathways were drawn, and DFT calculations, were performed to assess the reactivity of each reaction intermediate. The influence of the deposition temperature on several characteristics of the process such as composition of the film and growth per cycle was also explained.