Role of Atomic and Electronic Structure of LiTaO$_{\mathrm{3\thinspace }}$and LiNbO$_{\mathrm{3}}$ Piezoelectric for Direct NanoBonding™ with Si And SiO$_{\mathrm{2}}$:~ Comparison of Measured Surface Energies with Computed $\Delta $G and Infra-Red Absorption

Piezoelectric LiTaO$_{\mathrm{3\thinspace }}$/LiNbO$_{\mathrm{3}}$/Si hetero-structures have two major issues: mismatch of crystal structure, lattice constants and especially coefficient of thermal expansion, by an order of magnitude.~Hence, this work uses NanoBonding$^{\mathrm{TM\thinspace }}$[1] to directly bond LiTaO$_{\mathrm{3}}$ to Si and LiNbO$_{\mathrm{3}}$ to SiO$_{\mathrm{2\thinspace }}$via Surface Energy Engineering (SEE). SEE modifies in synergy surface hydro-affinity (H-A) and Surface Energy (SE) to far-from-equilibrium states likely to react in air at RT. HA and SE are measured via Three Liquid Contact Angle Analysis in air. SEs are 41 \textpm 2 mJ/m$^{\mathrm{2\thinspace }}$for LiTaO$_{\mathrm{3}}$ and 39 \textpm 2.5 mJ/m$^{\mathrm{2}}$ for LiNbO$_{\mathrm{3}}$, thus close. SE is compared to computed $\Delta $Gs of interaction for LiTaO$_{\mathrm{3}}$, -104 mJ/m$^{\mathrm{2}}$, and LiNbO$_{\mathrm{3}}$, -115 mJ/m$^{\mathrm{2}}$, in 25{\%} H$_{\mathrm{R}}$. Thus, $\Delta $Gs favor water adsorption with negative values, -104 mJ/m$^{\mathrm{2}}$ and -115 mJ/m$^{\mathrm{2\thinspace }}$respectively.~Negative $\Delta $G can favor spontaneous bonding of LiTaO$_{\mathrm{3}}$ to Si and hydrophobic LiNbO$_{\mathrm{3}}$ to hydrophilic SiO$_{\mathrm{2}}$. Experimentally, SEE is needed to activate bonding of LiTaO$_{\mathrm{3}}$ to Si, and LiNbO$_{\mathrm{3}}$ to SiO$_{\mathrm{2}}$. [1] Herbots, et al. U.S. Pat. {\#} 9,018,077 (2015), 9,589,801(2017), pend. (2020)