Advantages of ALD over evaporation deposition for high-k materials integration in high power capacitive RF MEMS

We report a study over a wide range of high-K dielectric materials (Al
x
O
y
, HfO
x
, TiO
x
…) deposited by different techniques (Evaporation, ALD, PEALD…) for high power RF applications. Main results show that ALD technique is matching the McPherson trend based on thermochemical prediction. Furthermore ALD materials are promising to meet high power requirements for capacitive RF MEMS switches. As a result, Thermal ALD HfO
2
was integrated in high power capacitive RF MEMS switches in order to improve their RF performances, power handling and reliability.