GaN Micromechanical Resonators with Meshed MetalBottom Electrode

Materials

Azadeh Ansari¹  Pei-Cheng Ku¹  Mina Rais-Zadeh¹  Che-Yu Liu²  Chien-Chung Lin²  Hao-Chung Kuo² 

[1] Department of Electrical Engineering and Computer Science, University of Michigan,Ann Arbor, MI 48109, USA;Department of Photonic & Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan;

关键词: gallium nitride (GaN) microelectromechanical (MEMS) resonators;    metal-organic chemical vapor deposition (MOCVD);    epitaxial growth;    piezoelectric;   

DOI  :  10.3390/ma8031204

来源: DOAJ

【 摘 要 】

This work describes a novel architecture to realize high-performance gallium nitride (GaN) bulk acoustic wave (BAW) resonators. The method is based on the growth of a thick GaN layer on a metal electrode grid. The fabrication process starts with the growth of a thin GaN buffer layer on a Si (111) substrate. The GaN buffer layer is patterned and trenches are made and refilled with sputtered tungsten (W)/silicon dioxide (SiO2) forming passivated metal electrode grids. GaN is then regrown, nucleating from the exposed GaN seed layer and coalescing to form a thick GaN device layer. A metal electrode can be deposited and patterned on top of the GaN layer. This method enables vertical piezoelectric actuation of the GaN layer using its largest piezoelectric coefficient (d33) forthickness-mode resonance. Having a bottom electrode also results in a higher coupling coefficient, useful for the implementation of acoustic filters. Growth of GaN on Si enables releasing the device from the frontside using isotropic xenon difluoride (XeF2) etch and therefore eliminating the need for backside lithography and etching.

【 授权许可】

Unknown