Patterning of hafnia and titania via gas-phase soft lithography combined with atomic layer deposition

Novel titania and hafnia structures on top of silica wafer were produced using atomic layer deposition through the accessible pores created by a patterned polydimethylsiloxane (PDMS) stamp in conformal contact. Typically, the processing temperature was in the range of 125 °C in order to avoid damaging the stamp and also to create an amorphous metal oxide deposit. Interestingly, the deposit formation tended to be dominated by condensation of the metal oxide precursor and water in the vicinity of the contact edges of the stamp and substrate. Upon removal of the stamp, the deposit patterns thus exhibited narrow features of much finer lateral resolution than the channel width of the stamp. Furthermore, it was demonstrated that oxide patterns of complex geometries were formed through the accessible pores.