The etching of La2O3, Al2O3, HfSiON, SiO2 and photoresist films in various concentrations of HCl and H2SO4 solutions was studied. The wet etch selectivity of La2O3 to other thin films was very high. The etch rate of La2O3 is strongly related to the H concentration in the both HCl and H2SO4 solutions. Further, the etching mechanism of La2O3 in HCl was investigated. The studys two major new findings are: i) etching of La2O3 thin films occurs in H2O containing LaCl3 without addition of HCl, which may result from the production of HCl in solution, and ii) addition of La(OH)3 in HCl suppresses the etch rate of La2O 3. Based on these experimental results, an etching reaction of La2O3 in HCl is proposed.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry