Wet Nano-Bonding of Silica-to-Si and Silica-to-Silica below 200$^{\circ}$ C by H2O catalysis and a 2-D precursor phase: TMAFM, Hydroaffinity and Surface Free Energy Analysis

Hydroxylated silica about 2.1 $\pm$ 0.1 nm thick are nucleated on OH(1x1)Si(100) as precursor phase to cross-bond directly silica to Si, and silica to silica using planarization via extended atomic terraces, T$\le $ 200$^{\circ}$C, an H2O/O2 ambient, and p $\ge $ 1 atm. This method,``Wet Nano-Bonding\texttrademark,'' relies on the Herbots-Atluri process [1] to nucleate precursor phases to bond via direct hydroxylated silica molecular cross-bridges two surfaces brought into contact at the nano-scale. Ordered Si2(OH)4 $\beta $-cristobalite precursor phases exhibit atomic terraces that extend to \textgreater 20 nm, in contrast to the 2 nm width in ``as received'' Si(100) wafers. $\beta $-cristobalite nano-phases can desorb at low temperatures (T \textless / $\sim$ 200$^{\circ}$ C) [3]. These ordered oxides can promote the growth of flatter, smoother, better controlled oxides at low temperatures in ambient air. When put into close contact at T$\ge $ 200$^{\circ}$ C with oxygen-deficient phases of SiOx used in microelectronics, they can consistently nucleate a cross-bridging between the two substrates, or ``nano-bonding'' inter-phase [4] between various combinations Si and silica provided an H2O/O2 ambient catalyzes low temperature oxidation and nano-contacting is achieved via pressurization in the nano-bonding chamber.