Influence of Flow Rates and Flow Times of Plasma-Enhanced Atomic Layer Deposition Purge Gas on TiN Thin Film Properties

Abstract

This study investigated the effect of purge gas flow rate and purge gas flow time on the properties of TiN thin films via chemical reaction simulation and the plasma-enhanced atomic layer deposition (PEALD) process along purge gas flow rates and time settings. Chemical reaction simulation unveiled an incremental increase in generating volatile products along purge gas flow rates. In contrast, increased purge gas flow times enhanced the desorption of physically adsorbed species flow time in the film surface. Subsequent thin film analysis showed that the increased Ar purge gas flow rate caused a shift of 44% in wafer non-uniformity, 46% in carbon composition, and 11% in oxygen composition in the deposited film. Modulations in the Ar purge gas flow time yielded variations of 50% in wafer non-uniformity, 46% in carbon composition, and 15% in oxygen content. Notably, 38% of the resistivity and 35% of the film thickness occurred due to experimental variations in the Ar purge step condition. Increased purge gas flow rates had a negligible impact on the film composition, thickness, and resistivity, but the film’s non-uniformity on a 6-inch wafer was notable. Extended purge gas flow times with inadequate flow rates resulted in undesired impurities in the thin film. This study employed a method that utilized reaction simulation to investigate the impact of purge gas flow and verified these results through film properties analysis. These findings can help in determining optimal purge conditions to achieve the desired film properties of PEALD-deposited TiN thin films.