Benefits of a thermal drift during atomic layer deposition of Al2O3 for C-Si passivation

Variation of the substrate temperature within the ALD window during deposition does not significantly impact the growth rate of Al
₂
O
₃
layers but changes their properties. Reduced initial deposition temperature allows storing hydrogen at the c-Si/Al
₂
O
₃
interface. This hydrogen is steadily released during the deposition of upper layers due to the increase of substrate temperature. Al
₂
O
₃
can thus provide SRV <;10 cm.s
^-1
in as-deposited state for a thermal budget below 250 °C. Thermal drift also prevents strong blistering caused by post-deposition thermal processes as most of the gases can be released during deposition, in the absence of a thick diffusion barrier.