Inductively coupled plasma reactive ion etching of bulk ZnO single crystal and molecular beam epitaxy grown ZnO films

Dry etching processes for bulk-single crystal zinc oxide (ZnO) and molecular beam epitaxy (MBE) grown ZnO have been investigated using inductively coupled plasma (ICP) of CH4 and SiCl4 based plasma chemistry. The CH4-based chemistry showed a higher etch rate than the SiCl4 based chemistry, presumably due to the formation of highly volatile metal organic zinc compound. The influence of base pressure, radio frequency table power, and ICP power on etch rate was studied. Auger electron spectroscopy has been employed to examine the surface stoichiometry of etched ZnO using both plasma chemistries. Furthermore, with optimized process parameters, the effect of plasma etching on the optical properties of MBE grown ZnO film is studied. An enhancement of the band edge luminescence along with almost complete suppression of defect level luminescence in hydrogen-containing plasma treated ZnO film has been observed.