Corroborating LiTaO$_{\mathrm{3}}$ Surface Energies Measured by Three Liquid Contact Angle Analysis (3LCAA) with Computed Gibbs Energy for Wafer Bonding Engineering

LiTaO3's piezo- and opto-electrical properties make its monolithic integration to Si key to the Internet of Things. In this work, Nano-Bonding (NB) uses Surface Energy (SE) Engineering to cross-bond LiTaO$_{\mathrm{3}}$ and Si/SiO$_{\mathrm{2}}$ at RT by engineering their surface energies and their hydro-affinity into far-from-equilibrium via Three Liquid Contact Angle Analysis (3LCAA). SE are found to average 41 $+$/- 2 mJ/m$^{\mathrm{2}}$ for hydrophobic LiTaO$_{\mathrm{3}}$, while wet etching yields 49 $+$/- 1.5 mJ/m$^{\mathrm{2}}$ for hydrophilic SiO$_{\mathrm{2}}$, and 53 $+$/- 0.2 mJ/m$^{\mathrm{2}}$ for hydrophilic Si. Thus hydrophobic-hydrophilic pairs can be engineered. $\Delta $G$_{\mathrm{LiTaO3-SiO2\thinspace }}$computed from SE is found to be negative at -8.18 mJ/m$^{\mathrm{2}}$ while $\Delta $G $_{\mathrm{LiTaO3-SiO2}}$ is -0.46 mJ/m$^{\mathrm{2}}$ at RT. Negative $\Delta $Gs favor bonding of hydrophobic LiTaO$_{\mathrm{3}}$, to hydrophilic Si and SiO$_{\mathrm{2}}$.