The Dry Etching Properties of HfAlO_3 Thin Films over Si and SiO_2 Using Inductively Coupled Plasma Source

摘要

In this work, we investigated the etching characteristics of HfAlO_3 thin films and the selectivity of HfAlO_3 to Si and SiO_2 in a CF_4/Ar inductively coupled plasma (ICP) system. The maximum etch rates of HfAlO_3 thin films was 36.7 nmlmin at a gas mixing ratio of CF_4/Ar ( = 20:80%). At the same time, the etch rate was measured as a function of the etching parameters, such as the RF power, DC-bias voltage and process pressure. The X-ray photoelectron spectroscopy analysis showed the efficient destruction of the oxide bonds by the ion bombardment, as well as the accumulation of low volatile reaction products on the etched surface. Based on these data, the ion-assisted chemical reaction was proposed as the etch mechanism for the CF_4-containing plasmas.