Wideband and high reliability RF-MEMS switches using PZT/HfO/sub 2/ multi-layered high K dielectrics

Capacitive RF MEMS switch dielectric charging and reliability: a critical review with recommendations

“…A kink is observed in the leakage current versus field curve at medium fields, below which the leakage current is more or less proportional to the field (TAT), and above which a fast increase is observed (Poole-Frenkel) [56]. HfO 2 A HfO 2 /PZT bilayer dielectric has shown a 10 3 times lower leakage current than SiN x , with a combined stack ε r ≈ 80 [58]. No switch reliability tests were reported for this configuration.…”

“…It was recognized early on that a suitable dielectric should either be so 'perfect' that no significant charging can take place during the operational life of the device, or it should be so leaky that accumulated charge leaks away immediately upon the removal of the stressing voltage, as described in a Texas Instruments patent [47]. Many materials have been evaluated for their suitability as an RF MEMS switch dielectric, such as several types of SiN x [40,41,[48][49][50][51][52], SiO 2 [53,54], high-k dielectrics, such as Ta 2 O 5 [55,56] and HfO 2 and oxynitride [57,58], a composite dielectric with carbon nanotubes (CNTs) in SiN x [59], and even nanocrystalline diamond (NCD) [60] and ultrananocrystalline diamond (UNCD) [61].…”

Development of hafnium oxynitride dielectrics for radio-frequency-microelectromechanical system capacitive switches

“…As one of the most promising candidate materials for the next generation of gate oxides, the HfO 2 dielectric has unmatched advantages over other high dielectric constant materials such as SrTiO 3 and barium-strontium-titanate, which have been used in RF-MEMS capacitive switches [5,6]. HfO 2 dielectric has been successfully used in RF-MEMS capacitive switches with excellent RF performance reported [7,8]. Amorphous dielectric materials are preferred for RF-MEMS capacitive switches for many good reasons such as better reliability.…”

An Overview of Reliability and Failure Mode Analysis of Microelectromechanical Systems (MEMS)

“…Additionally, measurements of PZT/HfO 2 multi-layered dielectrics showed the expected high dielectric constant for high switching isolation and low leakage current for very low operating power consumption. From bias-stressing tests, PZT/HfO 2 was verified as having significantly better dielectric characteristics in very low charging effects and a long lifetime in comparison to Si 3 N 4 [57].…”