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Tungsten (W) film is increasingly utilized in various microheater applications due to its numerous advantages. These advantages include a high melting point, positive constant temperature coefficient of resistance (TCR), good mechanical stability, and compatibility with semiconductor processes. In this paper, deposition parameters for enhancing the properties of W film were investigated, and an optimized microheater was fabricated. It was found that the deposition temperature and pressure can modify the TCR to be negative or positive and the crystalline phase of W films to be alpha phases or mixed with beta phases. A W film deposited under 650 °C with a pressure of 1 pa has a positive TCR and pure alpha phase crystalline structure. We applied this optimized W film as a microheater in an RF phase-change switch (RFPCS), and the maximum voltage of the optimized W microheater increased by at least 48% in this work. By optimizing the microheater, the phase-change switch can be successfully actuated in both on and off states, demonstrated by the Raman results of the phase-change material. A voltage pulse of 20 V/200 ns was enough to turn the switch off with MΩ, and 11 V/3 μs could turn the switch on with 138 Ω. The optimized microheater and device can cycle 500 times without failure. The insertion loss and isolation of the device at 20 GHz was 1.0 dB and 22 dB. [ABSTRACT FROM AUTHOR]

Multilayer ceramic capacitors (MLCCs) prepared using Ba1−xSrxTiO3 (BST) ceramics exhibit high dielectric constants (~1000), low dielectric loss (<0.01), and high breakdown voltage, with particularly significant tunability in dielectric properties (>50%) and with poor temperature stability. Doping-dominated temperature stability improvements often result in unintended loss of dielectric properties. A non-doping method has been proposed to enhance the temperature stability of BST capacitors. The composite gradient multilayer (CGML) ceramic capacitors with BaxSr1−xTiO3, where 0.5 < x < 0.8, as the dielectric, were prepared using a tape-casting method and sintered at 1250 °C. There exists a dense microstructure and continuous interface between the BaxSr1−xTiO3 thick film and the Pt electrodes. CGML ceramic capacitors feature a high dielectric constant at 1270, a low dielectric loss of less than 0.007, and excellent frequency and temperature stability. The capacitor showcases remarkable dielectric properties with a substantial tunability of 68% at 100 kV/cm, along with a notably consistent tunability ranging from 20% to 28% at 15 kV/cm across temperatures spanning from 30 to 100 °C, outperforming single-component BST-MLCCs in dielectric performance. [ABSTRACT FROM AUTHOR]

(1-x)(Pb0.97La0.02)(Zr0.46Sn0.48Ti0.06)O3-xSiO2 ((1-x)PLZST-xSiO2, x = 0-0.025) thick film antiferroelectric ceramics were preapred by a traditional solid-state reaction method. The structure and dielectric properties related to the energy storage density in the (1-x)PLZST-xSiO2 system were investigated in detail. PLZST with 0.5%SiO2 content is superior to other SiO2 contents samples in terms of the structure, dielectric properties and phase transition modulation. The energy storage density reaches the maximum value of 1.66 J/cm3 accompanied by the energy efficiency of 86.92% in 0.995 PLZST-0.005SiO2. The results suggest that high energy storage density of PLZST system can be improved with phase transition modulation using SiO2. There is a large decrease in grain size after SiO2 doping. Modest phase transition modulation was achieved by introducing SiO2. The 0.995PLZST-0.005SiO2 sample has a good advantage over other SiO2 content samples in terms of the structure, dielectric properties and modest modulation of phase transition. [ABSTRACT FROM AUTHOR]