Reducing AC impedance measurement errors caused by the DC voltage dependence of broadband high-voltage bias-tees

During the AC impedance characterization of devices, from the kHz-range up to the GHz-range, accuracy can be lost when a DC voltage is applied. Commercial high-voltage broadband bias-tees are often voltage-dependent, which can cause inaccuracies at low frequencies. A calibration technique with applied bias significantly improves the measurement accuracy.\ud Additionally, a bias-tee has been developed with a voltageindependent capacitor, suitable for DC voltages up to 500 V showing excellent performance up to several gigahertz. PIN diode limiters protect the measurement equipment from damage in case of a device breakdown.\u

On the Trade-Off Between Quality Factor and Tuning Ratio in Tunable High-Frequency Capacitors

A benchmark of tunable and switchable devices at microwave frequencies is presented on the basis of physical limitations to show their potential for reconfigurable cellular applications. Performance limitations are outlined for each given technology focusing on the quality factor (Q) and tuning ratio (eta) as figures of merit. The state of the art in terms of these figures of merit of several tunable and switchable technologies is visualized and discussed. If the performance of these criteria is not met, the application will not be feasible. The quality factor can typically be traded off for tuning ratio. The benchmark of tunable capacitor technologies shows that transistor-switched capacitors, varactor diodes, and ferroelectric varactors perform well at 2 GHz for tuning ratios below 3, with an advantage for GaAs varactor diodes. Planar microelectromechanical capacitive switches have the potential to outperform all other technologies at tuning ratios higher than 8. Capacitors based on tunable dielectrics have the highest miniaturization potential, whereas semiconductor devices benefit from the existing manufacturing infrastructure

Fast RF-CV characterization through high-speed 1-port S-parameter measurements

We present a novel method to measure the capacitance-voltage relation of an electronic device. The approach is accurate, very fast, and cost-effective compared to the existing off-the-shelf solutions. Capacitances are determined using a single-frequency 1-port S-parameter setup constructed from discrete components. We introduce a new way to correct for non-linearities of the used components, which greatly increases the accuracy with which the phase and magnitude of the reflected signal is measured. The measurement technique is validated on an RF-MEMS capacitive switch and a BST tunable capacitor. Complete capacitance-voltage curves are measured in less than a millisecond, with a measurement accuracy well below 1%.\ud \u

Separation of intrinsic dielectric and resistive electrode losses in ferroelectric capacitors at radio frequencies

To analyze the intrinsic dielectric performance of planar high-density capacitors at radio frequencies (RF), the dielectric losses need to be distinguished from the resistive electrode losses. The resistive losses of the electrodes at RF are de-embedded employing a linear regression procedure with partial compensation for distributed effects. We use tunable ferroelectric capacitors with a barium strontium titanate (BST) dielectric with an inner diameter d ≥ 8 μm on a silicon substrate. The de-embedding of the electrode losses has been successfully performed utilizing 1-Port RF measurement data from of an Advantest R3767CG vector network analyzer (VNA) in the frequency range of 10 MHz – 8 GHz

Thin film barium strontium titanate capacitors for tunable RF front-end applications

In this thesis, the results of intensive electrical characterization, modeling and the design of hardware with thin film tunable capacitors, i.e., dielectric varactors, has been presented and discussed. Especially the quality factor Q and the tuning ratio of the tunable capacitors have been studied, since these are crucial parameters for reconfigurable RF front-end applications for mobile phones

Reducing AC impedance measurement errors caused by the DC voltage dependence of broadband high-voltage bias-tees

During the AC impedance characterization of devices, from the kHz-range up to the GHz-range, accuracy can be lost when a DC voltage is applied. Commercial high-voltage broadband bias-tees are often voltage-dependent, which can cause inaccuracies at low frequencies. A calibration technique with applied bias significantly improves the measurement accuracy. Additionally, a bias-tee has been developed with a voltageindependent capacitor, suitable for DC voltages up to 500 V showing excellent performance up to several gigahertz. PIN diode limiters protect the measurement equipment from damage in case of a device breakdown

Informe sobre les VII Jornadas Españolas de Documentación, FESABID 2000 (Bilbao, 19-21 d'octubre de 2000)

Aquestes jornades espanyoles de documentació tenen lloc cada dos anys en una localitat diferent d'Espanya, i són organitzades conjuntament per FESABID (Federación Española de Sociedades de Archivística, Biblioteconomía, Documentación y Museística) i l'associació professional de la comunitat autònoma on se celebren. En aquesta ocasió, Bilbao fou la ciutat amfitriona, i ALDEE (Artxibozain, Liburuzain eta Dokumentazainen Euskal Elkartea), una de les associacions professionals que existeixen al País Basc, participà en l'organitzaci

BaxSr1−xTi1.02O3 metal–insulator–metal capacitors on planarized alumina substrates

Nanocrystalline barium strontium titanate (BaxSr1−xTi1.02O3) thin films with a barium content of x=0.8, 0.9 and 1 have been fabricated in a metal–insulator–metal configuration on glass-planarized alumina substrates.\ud Cost-effective processing measures have been utilized by using poly-crystalline alumina substrates, wetchemical processing of the dielectric, and by a small physical area of the ferroelectric capacitors (as low as 50 μm2 for radio frequencies measurements). Glass-planarization on alumina ceramic substrates enables barium strontium titanate films with high quality and homogeneity. We mainly focus on fine-tuning the electrical performance in the low gigahertz range (<10 GHz). Extensive micro-structural and electrical characterization has been performed. Micro-structural information is obtained by: Transmission Electron Microscopy, Scanning Electron Microscopy and X-ray diffraction. The dielectric response is investigated as a function of temperature, frequency and electric field for each sample. We measured a relatively constant permittivity for typical operating temperatures of applications. The quality factor Q is between 21 and 27 at 1 GHz at zero DC bias and the tuning ratio η between 1.8 and 2.2 at |E|=0.4 MV/cm.\u

Electrical characterization of thin film ferroelectric capacitors

Tunable capacitors can be used to facilitate the reduction of components in wireless technologies. The tunability of the capacitors is caused by the sensitivity of the relative dielectric constant to a change in polarization with electric field. Thin film ferroelectric MIM capacitors on silicon offer a re-use of electronic circuitry, low tuning voltages, a high capacitance density, a low cost, a presence of bulk acoustic wave resonance(s) and decoupling functionality. The basic operation and measurement principles are outlined. To assess the performance in the microwave frequency range, MIM test structures1, with a barium strontium titanate dielectric, have been successfully processed, and measured. The electrical characterization of tunable capacitors is demonstrated using a 1-Port Advantest R3767CG VNA in the frequency range of 10 MHz – 8 GHz