In Situ Cycle-by-Cycle Flash Annealing of Atomic Layer Deposited Materials

This work establishes a modified atomic layer deposition (ALD) method, adding a rapid high temperature annealing step during every cycle of deposition without adding significant time to the overall reaction. To achieve the ultrafast heating requirement, an in situ flash lamp annealing (FLA) apparatus was designed and integrated into the lid of an ALD chamber. The FLA ALD technique was applied to modify the morphology and crystallinity of as-deposited PbS quantum dot (QD) structures and thin TiO₂ films. The ability to control the PbS QD size, shape, and standard deviation in size as a function of FLA conditions was observed. Furthermore, the FLA technique enabled the direct ALD growth of crystalline TiO₂ thin films, which were amorphous as-deposited. This technique provides a new opportunity to facilitate diffusion and crystallization throughout the ALD growth process while maintaining the low temperatures required during the self-limiting surface reactions.