Direct bonded quartz resonators

In contrast to other methods direct bonding allows for the joining of two materials without an intermediate layer as in soldering or gluing. Although often putting tremendous requirements on the surfaces to be joined in terms of cleanliness and smoothness - direct bonding generally provides extraordinary adhesion and stability. In the semiconductor industry the direct bonding of silicon has been successfully employed for many years. Recently we showed that the technology, with some modifications, could be applied also to single crystalline quartz, and that the direct bonding of quartz could be achieved with arbitrary cuts and in various directions. The ability to unite quartz wafers ultimately enables new resonator, filter, and sensor concepts, and the ability to bond pre-processed wafers make true all-quartz packages possible. In present work, we investigate the influence on a resonator by including a direct bonded interface.