Atomic layer deposition of tin oxide thin films from bis[bis(trimethylsilyl)amino]tin(II) with ozone and water

Tin oxide thin films were grown by atomic layer deposition (ALD) from bis[bis(trimethylsilyl)
amino]tin(II) with ozone and water. The ALD growth rate of tin oxide films was examined with
respect to substrate temperature, precursor doses, and number of ALD cycles. With ozone two
ALD windows were observed, between 80 and 100 C and between 125 and 200 C. The films
grown on soda lime glass and silicon substrates were uniform across the substrates. With the water
process the growth rate at 100–250 C was 0.05–0.18A ° /cycle, and with the ozone process, the
growth rate at 80–200 C was 0.05–0.11A ° /cycle. The films were further studied for composition
and morphology. The films deposited with water showed crystallinity with the tetragonal SnO
phase, and annealing in air increased the conductivity of the films while the SnO2 phase
appeared. All the films deposited with ozone contained silicon as an impurity and were
amorphous and nonconductive both as-deposited and after annealing. The films were further
deposited in TiO2 nanotubes aiming to create a pn-junction which was studied by I-V measurements.
The TiO2 nanostructure functioned also as a test structure for conformality of the
processes.