Integrated acoustic bandgap devices for energy confinement and methods of fabricating same

Abstract

The present invention is directed to monolithic integrated circuits incorporating an oscillator element that are particularly suited for use in timing applications. The oscillator element includes a resonator element having a piezoelectric material disposed between a pair of electrodes. The oscillator element also includes an acoustic confinement structure that may be disposed on either side of the resonator element. The acoustic confinement element includes alternating sets of low and high acoustic impedance materials. A temperature compensation layer may be disposed between the piezoelectric material and at least one of the electrodes. The oscillator element is monolithically integrated with an integrated circuit element through an interconnection. The oscillator element and the integrated circuit element may be fabricated sequentially or concurrently.

1 . An integrated circuit device comprising:
 a circuit element means having a resonator means and an acoustic confinement means for preventing the ultrasonic wave from propagating away from the resonator means; and   an integrated circuit means having a interconnect means;   wherein the circuit element means is monolithically connected to the integrated circuit means in a unitary structure.   
     
     
         2 . The integrated circuit of  claim 1  wherein the resonator means has first and second electrodes and wherein one of the first and second electrodes is electrically connected to the integrated circuit interconnect means. 
     
     
         3 . The integrated circuit device of  claim 1  wherein the circuit element means further comprises a temperature compensation means. 
     
     
         4 . The integrated circuit of  claim 1  wherein the acoustic confinement means provides the circuit element means with a bandgap at a predetermined frequency f 0 . 
     
     
         5 . The integrated circuit of  claim 4  wherein, in operation, the resonator means vibrates within the acoustic confinement means. 
     
     
         6 . The integrated circuit of  claim 1  wherein the resonator means and the acoustic confinement means form an acoustic band gap structure. 
     
     
         7 . The integrated circuit of  claim 4  wherein the acoustic confinement means has a peak reflectivity at the predetermined frequency f 0 . 
     
     
         8 . The integrated circuit of  claim 1  wherein the acoustic confinement means is a package for the resonator means. 
     
     
         9 . The integrated circuit of  claim 1  wherein the circuit element means is an oscillator means. 
     
     
         10 . The integrated circuit of  claim 1  wherein the circuit element means is a filter means. 
     
     
         11 . The integrated circuit of  claim 9  wherein the circuit element means is an oscillator means and a filter means.