Fabrication of HfO2 patterns by laser interference nanolithography and selective dry etching for III-V CMOS application
1 Instituto de Ciencia de Materiales de Madrid, CSIC. C/Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
2 Instituto Madrileño de Estudios Avanzados de Materiales (Instituto IMDEA-Materiales). C/Profesor Aranguren, s/n. 28040 Madrid, Spain
3 Tyndall National Institute, University College Cork, Lee Maltings Complex, Prospect Row, Cork, Ireland
Nanoscale Research Letters 2011, 6:400 doi:10.1186/1556-276X-6-400Published: 31 May 2011
Nanostructuring of ultrathin HfO2 films deposited on GaAs (001) substrates by high-resolution Lloyd's mirror laser interference nanolithography is described. Pattern transfer to the HfO2 film was carried out by reactive ion beam etching using CF4 and O2 plasmas. A combination of atomic force microscopy, high-resolution scanning electron microscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy microanalysis was used to characterise the various etching steps of the process and the resulting HfO2/GaAs pattern morphology, structure, and chemical composition. We show that the patterning process can be applied to fabricate uniform arrays of HfO2 mesa stripes with tapered sidewalls and linewidths of 100 nm. The exposed GaAs trenches were found to be residue-free and atomically smooth with a root-mean-square line roughness of 0.18 nm after plasma etching.
PACS: Dielectric oxides 77.84.Bw, Nanoscale pattern formation 81.16.Rf, Plasma etching 52.77.Bn, Fabrication of III-V semiconductors 81.05.Ea