Abstract :
The dry etching characteristics of bulk, single-crystal zinc-oxide (ZnO) and rf-sputtered indium–zinc-oxide (IZO) films have been investigated
using an inductively coupled high-density plasma with different plasma chemistries. The introduction of interhalogens such as ICl, IBr, BI3, and
BBr3 to the Ar plasma produced no enhancement of the ZnO and IZO etch rates with respect to physical sputtering in a pure argon atmosphere
under the same experimental conditions. In these plasma chemistries, the etch rate of both materials increased with source power and ion energy,
indicating that ion bombardment plays an important role in enhancing desorption of etch products. Except in Ar/CH4/H2 discharges, the ZnO etch
rate was very similar to that of IZO, which indicates that zinc and indium atoms are driven by a similar plasma etching dynamic. CH4/H2-containing
plasmas produced higher etch rates for IZO than for ZnO due to the preferential desorption of the group III etch products. Application of the CH4/
H2/Ar plasma to the etching of deep features in bulk, single-crystal ZnO produced highly anisotropic profiles although some trenches were
observed near the sidewalls
