Abstract
We study the impact of ozone-based Al2O3 Atomic Layer
Deposition (ALD) on the surface passivation quality of
crystalline silicon. We show that the passivation quality
strongly depends on the ozone concentration: the higher
ozone concentration results in lower interface defect
density and thereby improved passivation. In contrast to
previous studies, our results reveal that too high
interface hydrogen content can be detrimental to the
passivation. The interface hydrogen concentration can be
optimized by the ozone-based process; however, the use of
pure ozone increases the harmful carbon concentration in
the film. Here we demonstrate that low carbon and optimal
hydrogen concentration can be achieved by a single
process combining the water- and ozone-based reactions.
This process results in an interface defect density of 2
* 1011 eV - 1 cm - 2, and maximum surface recombination
velocities of 7.1 cm/s and 10 cm/s, after annealing and
after an additional firing at 800 °C, respectively. In
addition, our results suggest that the effective oxide
charge density can be optimized in a simple way by
varying the ozone concentration and by injecting water to
the ozone process.
Original language | English |
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Pages (from-to) | 2402-2407 |
Journal | Applied Surface Science |
Volume | 357, Part B |
DOIs | |
Publication status | Published - 2015 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Atomic Layer Deposition
- Al2O3
- ozone
- surface passivation
- interface