Chrarcterization of ALN and ALSCN film ICP etching for micro/nano fabrication

Abstract We investigate the inductively coupled plasma (ICP) etching characteristics of (0002) Aluminum Nitride (AlN) and Aluminum Scandium Nitride (Al0.94Sc0.06N) piezoelectric thin films as well as the implementation on piezoelectric lamb wave resonators. A profile of 84° is obtained on AlN thin film, with an etching rate of approximately 230 nm/min, and a selectivity of 0.77:1 relative to photoresist mask. A nearly 80° profile and over 30:1 selectivity are accomplished using Ni film as the etching mask. Al0.94Sc0.06N film has achieved a profile of 77° by optimizing the RF power. Finally, AlN contour mode resonators (CMRs) are fabricated and characterized, and a CMR operating at about 400 MHz with a quality factor exceeding 1600 has been demonstrated.