Development of Thick Sc0.2Al0.8N Film for MEMS Application

The integration of new material for any device as a structural and packaging material invariably requires a lot of development for deposition, etching, and cleaning etc. This procedure becomes more critical with the increase in material thickness. This work reports the development of a 1.3 µm thick Sc
0.2
Al
0.8
N film deposition by sputtering. The film was optimized to reduce the number of Abnormally Oriented Grains (AOG) in the film by using pre-treatment conditions before the deposition of the film. The results show a tremendous reduction in the number of AOG. The optimized 1.3 µm thick Sc
0.2
Al
0.8
N film is used in the optimization of the dry etching process using the ICP technique with photoresist as a mask on an 8-inch wafer. The etch recipe was optimized for focusing on reduced etch time and better selectivity with photoresist. The developed recipes were successfully applied to fabricate the GHZ range transducers with molybdenum (Mo) as a routing layer. Subsequent electrical measurements on the fabricated transducer devices confirmed the successful integration of 1.3 µm thick Sc
0.2
Al
0.8
N, demonstrating its potential for MEMS applications.