Status and new evaluation method of interfacial oxide between the directly-bonded Si wafer pairs

We discovered that the shapes of the (111) facet structures were closely related to the disintegration, the spheroidization, and the stabilization of the native interfacial oxide layer in directly bonded Si wafer pairs. These (111) facet structures are generated from the anisotropic etching of (110) cross-section of bonded (100) Si wafer pairs. Also, we confirmed that most of the interfacial oxide existing at the bonding interface of a well-aligned wafer pairs were disintegrated and spheroidized by high-temperature annealing process above 900°C