In-situ scanning transmission electron microscopy study of Al-amorphous SiO2 layer-SiC interface

Here, we present a comprehensive study on atomic-scale in-situ biasing/heating scanning transmission electron microscopy ((S)TEM) of Al-amorphous SiO 2 –SiC interface. The investigation includes electrical, chemical, and structural analysis of the interface at different temperatures (25–600 °C). The results show that at ~ 500 °C the electrical (three-orders of magnitude resistivity drop), chemical (dissolution of SiO 2 amorphous layer), and microstructural features ( e.g. formation of Al 2 O 3 , Si and Al 4 C 3 ) of the interface start to change. According to the results, amorphous SiO 2 dissolves in Al, leading to formation of α-Al 2 O 3 and Si within the Al. In contrast, elemental interdiffusion (Al 3+ ⇄ Si 4+ ) between Al and SiC occurs resulting in formation of Al 4 C 3 . From the results, we can infer that reaction mechanism between Al and crystalline SiC is different with that between Al and SiO 2 amorphous phase. It is believed that structural similarities between SiC and Al 4 C 3 play an important role in paving the way for elemental interdiffusion.