Paper PS+TF-MoM10
Capacitively Coupled DC/RF Discharges for PEALD Process of Titanium Dioxide Films

Monday, October 22, 2018, 11:20 am, Room 104C

We are working on the development of a discharge source using tailored waveforms for plasma enhanced atomic layer deposition (PEALD) processes. The discharge sources employed in this study are 13.56 MHz RF, pulsed DC or their combination ^[1], and their applicability to PEALD process of titanium dioxide (TiO₂) thin films has been evaluated. A titanium precursor adsorbed on a silicon substrate having amorphous carbon (a-C) patterns is oxidized by applying these discharges in argon/oxygen mixtures. Thus PEALD process of TiO₂ films is achieved accordingly. The experimental results obtained from scanning transmission electron microscope show that TiO₂ films are deposited with excellent step coverage independent of the discharge sources. However, the film characteristics at each deposition position of a-C patterns (i.e. at the top, side and bottom) greatly vary depending on the discharge sources, which has been confirmed by the evaluation of the wet etching rate using a diluted hydrogen fluoride solution. The clear variation of the film characteristics is presumably attributed to the change in the number density of reactive species (electrons, ions, radicals), their ratio and the ion angle distributions, all of which are determined by the discharge sources.