Deposition temperature dependence of titanium oxide thin films grown by remote‐plasma atomic layer deposition

Abstract

Titanium dioxide (TiO 2 ) thin films were deposited by remoteplasma atomic layer deposition (RPALD). The process window was determined in the range from 150 to 300 8C for atomic layer deposition of TiO 2 thin film. The crystal structure and grain size of the TiO 2 thin films deposited by RPALD was controlled via the variations of the deposition temperature and post-deposition thermal annealing. The as-deposited TiO 2 thin film grown at 150 8C was amorphous whereas the TiO 2 thin films grown above 200 8C were polycrystalline, consisting of anatase phase. As the deposition temperature increased, the grain size of the anatase phase progressively decreased. Meanwhile, when annealed at 900 8C, the amorphous TiO 2 thin film deposited at 150 8C crystallized into anatase structure. The film deposited at 200 8C retained the anatase structure up to 900 8C while incurring minimal grain growth. However, the post-annealed TiO 2 thin films deposited at 250 and 300 8C partially transformed to the rutile structure, resulting in a mixture of anatase and rutile phases. It is speculated that the relatively large grain size of the films deposited below 200 8C likely suppressed the anatase ! rutile transformation during annealing as the reduction of total fraction of grains boundaries, which acted as primary nucleation sites for the rutile transition, delayed the anatase ! rutile transformation.

Enhanced Performance of MoS2 Photodetectors by Inserting an ALD‐Processed TiO2 Interlayer

“…We attribute the smooth interface to the orderly stacking of the Ti and O atoms into vacancies and dislocations during the ALD process at 200 °C. The SAED pattern of the TiO 2 /MoS 2 device (shown in Figure f) has clearer circular shape compared to the bare MoS 2 device, indicating the existence of a polycrystalline TiO 2 ultrathin film …”

Low temperature temporal and spatial atomic layer deposition of TiO2 films

“…49,50 In comparison to the water process, plasma deposition helps to decrease overall process time by decreasing the purge time after oxidant precursor exposure. There also exists the possibility of generating water during plasma-assisted ALD, due to the reaction of the oxygen radicals with hydrocarbons from the TTIP, but the amount of water that is produced in this case is does not significantly affect the process time.…”

Effect of substrate type on structure of TiO2 thin film deposited by atomic layer deposition technique

“…However, in thin film form, only anatase and rutile structures are more easily synthesized [1,6]. Anatase and rutile phases consist of interconnected TiO 6 octahedral chains that are interconnected in different configurations, resulting in different physical and chemical properties [3,7]. Due this, they are potentially attractive in different areas.…”