Optimization of AlN and AlScN Film ICP Etching

We present the inductively coupled plasma (ICP) etching characteristics of (0002) oriented Aluminum Nitride (AlN) and Aluminum Scandium Nitride (Al
_0.94
Sc
_0.06
N) piezoelectric thin films and implementation in AlN piezoelectric lamb wave resonators. A profile of 84° with an etching rate of about 230nm/min using Cl
₂
/ BCl
₃
/N
₂
mixed gas is achieved at AlN film, and a profile of 77° using same mixed gas is obtained at Al
_0.94
Sc
_0.06
N film. Finally, we demonstrate the fabrication and characteristics of AlN contour mode resonators (CMRs), and report a CMR operating at approximately 400MHz with the quality factor exceeding 1600.