Patent ID: 6548942
Filing Date: 2003-04-15
Classification: H03H

Abstract:
A microelectronic device, comprising:a substrate, and the substrate comprises silicon; a piezoelectric resonator disposed on the substrate, the piezoelectric resonator comprises a first electrode layer of metal deposited on the silicon, a layer of piezoelectric material deposited over the first electrode layer, and a second electrode layer of metal deposited over the piezoelectric material layer; an acoustic reflector located over and coupled to the piezoelectric resonator; an encapsulant comprising a molding compound having a low acoustic impedance, the encapsulant deposited over and encapsulating the piezoelectric resonator and acoustic reflector, the encapsulant making contact with the acoustic reflector; the acoustic reflector transforms the low acoustic impedance of the encapsulant into a high acoustic impedance at the acoustic resonator/acoustic reflector interface; and wherein the acoustic reflector comprises alternating acoustic reflecting layers of first and second acoustic impedance materials deposited over the second electrode layer of metal; the first acoustic impedance being higher than the second acoustic impedance.