Microstructural investigations of Y2O3 thin films deposited by laser ablation on MgO

The epitaxial relationships and the microstructure of thin Y2O3 fillm, in S itu grown by laser ablation at 700 degreesC under 0.5 mbar oxygen pressure on MgO substrate, are studied by X-lay and HRTEM investigations. X-ray phi -scan experiments show that Y2O3 exhibits two different crystallographic gr owing directions (111) and (100) on (100) single-crystalline MgO substrate. The (111) growing direction appears with four different epitaxial relation ships where the (110) Y2O3 in-plane direction is parallel to the (110) inpl ane direction of MgO. The (100) growing direction appears with one epitaxia l relationship, cube Y2O3 on cube MgO. The HRTEM experiments show the colum nar aspect of the Y2O3 thin film. Both (111) and (100) Y2O3-oriented grains are observed in good agreement with the X-ray experiments.