Effect of the blistering of ALD Al2O3 films on the silicon surface in Al-Al2O3-Si structures

Blistering of 11 nm and 45 nm-thick Al₂O₃ layers deposited by ALD on silicon substrates is studied in Al-Al₂O₃-Si structures fabricated using a field isolated process. Blisters are shown to be unevenly distributed and with different dimensions depending on the structure area. After chemical etching down to silicon, round voids are revealed underneath the blisters depending on the etchant used, indicating that some chemical reaction occurs at the Al₂O₃-Si interface at the blistered sites.