Direct-patterning SnO2 deposition by atomic-layer additive manufacturing†

The ALD precursor tetrakis(dimethylamido)tin and water are exploited towards the atomic-layer additive manufacturing (ALAM) of SnO₂ lines. ALAM exploits the surface chemistry principles of ALD (atomic layer depositions) but adds a laterally constrained precursor delivery. Motion of the precursor delivery nozzle over the substrate surface thus deposits the material in a 3D printing mode while maintaining the sub-nanometers thickness control of ALD. We find that the precursor canister temperature can be lowered by approximately 20 °C from ALD to ALAM, corresponding to a lower precursor consumption. The temperature window of controlled deposition reaches from 150 °C to 250 °C, whereas 200 °C yields the best stoichiometry and highest growth rate. The material is amorphous initially and crystallizes upon annealing at 500 °C in N₂ or air. The lines deposited have a flat top profile and a constant thickness along their length.