Wafer bonding strength increased by mobile ions
Paper in proceedings, 2009
Mechanical bonding energies of oxygen plasma treated and
room temperature wafer bonded silicon surfaces have been
measured as a function of storage time in parallel with
measurements of electrical interface properties. We find that the surface energy increases with a time dependence similar to that of decreasing interface state concentration. The current versus voltage behaviour reveals the existence of mobile ions. We conclude that these mobile charges after reaction with the interface states give rise to the increased surface energy responsible for the bonding.