| Abstract: | An amplifying radiofrequency device includes a piezoelectric film and a
semiconductor amplifier layer. The piezoelectric film is conformed as an
acoustic waveguide. The piezoelectric film has a principal acoustic
propagation direction parallel to the principal conduction direction of
the amplifier layer. Interdigitated transducers are positioned on the
piezoelectric film to respectively launch an acoustic wave in response to
an input RF signal, and transduce the acoustic wave back to an output RF
signal. There is a distance of less than the acoustic wavelength between
the semiconductor amplifier layer and the piezoelectric film. The
piezoelectric film has a thickness of less than the acoustic wavelength.
According to a method for making such a device, a stack of III-V layers
is epitaxially grown on a III-V substrate, wherein the stack comprises a
first etch stop layer, a second etch stop layer, an amplifier layer, and
a contact layer. The stack is bonded to a lithium niobate film. The III-V
substrate is removed by etching down to the first etch stop layer.
Deposition windows are opened by etching from the first etch stop layer
down to the contact layer. Metal contact electrodes are deposited in the
deposition windows. |