Techniques for monolithic co-integration of thin-film bulk acoustic resonator devices and III-N semiconductor transistor devices

摘要

Techniques are disclosed for co-integrating thin-film bulk acoustic resonator (TFBAR, also called FBAR) devices and III-N semiconductor transistor devices. In accordance with some embodiments, a given TFBAR device may include a superlattice structure comprising alternating layers of an epitaxial piezoelectric material, such as aluminum nitride (AlN), and any one, or combination, of other III-N semiconductor materials. For instance, aluminum indium nitride (Al_xIn_1-xN), aluminum gallium nitride (Al_xGa_1-xN), or aluminum indium gallium nitride (Al_xIn_yGa_1-x-yN) may be interleaved with the AlN, and the particular compositional ratios thereof may be adjusted to customize resonator performance. In accordance with some embodiments, the superlattice layers may be formed via an epitaxial deposition process, allowing for precise control over film thicknesses, in some cases in the range of a few nanometers. In accordance with some embodiments, one or more such TFBAR devices may be formed alongside III-N semiconductor transistor device(s), over a commonly shared semiconductor substrate.