硅-硅直接键合界面上SiO_2的非稳定性

Instability of Interfacial SiO_2 in Silicon Wafer Direct Bonding

对硅一硅直接健合界面上的SiO2进行了研究。借助高真空的AES和高分辨率的SEM显微分析观察到界面上的SiO2化学组成为非化学计量比的SiO1.5，以类球形小岛状均匀分布于键合界面上，平均半径远大于界面自然氧化层。对界面SiO2的理论分析表明，为了降低界面自由能，界面SiO2必然最大限度地减少其表面积，从而以类球形小岛分布于界面上，其平均半径至少大于自然氧化层的1.5倍。假定平衡界面因子为12时，同时考虑氧扩散引起的SiO2融解和界面自由能减小引起的成核长大效应，理论计算与实验结果相吻合。

The interfacial SiO2 if layer of Silicon-to-SiIicon direct bonding(SDB) has been studied in this paper by means of AES and SEM of interfacial SiO2. It is found experirnentally that SiO2 disintegrates into sphere-shaped-like islands with average radius much larger than L, the thickness of the native oxide layet, and of amorphotis materials, SiO1.5. The theoretic analysis shows that SiO2 spontaneously disintegrates into islands because the interface free energy will decrease as much as possible.