Philippe Renaux

Dielectrical properties of metal-insulator-metal aluminum nitride structures: Measurement and modeling

The electrical properties of polycrystalline aluminum nitride (AlN) films grown by reactive dc magnetron sputtering are investigated in the transient and the steady-state regimes through metal-insulator-metal (MIM) structures with molybdenum (Mo) as metal electrodes. Measurements of current-time, current-voltage, and current-temperature characteristics are performed on AlN MIM structures. The extracted dielectric constant is 9.9. The transient current is observed to follow the empirical Curie–Von Schweidler law and its dependence on the applied field and the operating temperature is modeled. The time approach result is compared with the frequency-approach result by measuring the permittivity dispersion for low frequencies. Also, all the leakage mechanisms in AlN are identified in the steady-state regime depending on the applied field range. For a low electric field, the conduction mechanism is the Ohmic regime and the AlN resistivity is estimated to be 2.1×1015 Ω cm at room temperature. For higher electri...

Solidly mounted resonators under high power study for reliability assessment

This work deals with BAW SMR reliability at high power levels. Experimental methods easy to set up in common RF laboratories are presented and validated. Experimental results concerning frequency shifts versus the dissipated power and the harmonics generation are reported. The main origins of these effects are discussed physically and conclusions in light of the obtained results about the characterization method and the device reliability are drawn.

Characterization of IN-IC integrable in-plane nanometer scale resonators fabricated by a silicon on nothing advanced CMOS technology

The paper reports on in-plane nanometer scale resonators fabricated on 8 inch industrial tools, with a process based on the advanced CMOS Front End Silicon On Nothing Technology. The aim is to propose totally integrated time reference functions realized by small size NEMS resonators. The measurement set-up, simulation and experimental results in the range of 100 MHz are presented. Environmental issues such as temperature and pressure influence on the resonator behavior are also investigated. Results are discussed and compared with analytic calculation, finite element and electrical simulations with good agreement. Work in progress focuses on improving the f.Q product, detection by the use of integrated MOSFET transistors, low voltage operation and in-IC integration.

Linear variation of aluminum nitride capacitance versus voltage induced by a piezoelectric-electrostrictive coupling

We report here the physical explanation of the unusual observed linear variation of AlN capacitance versus voltage bias: a third order coupling between piezoelectricity and electrostriction. A phenomenological model based on free energy consideration is proposed in order to implement the electrostrictive effect together with the piezoelectric one. This model allows the accurate determination of the electrostrictive coefficient of interest by two independent ways (Q13=0.094 m4 C−2), giving high confidence in the physical explanation proposed.

Self heating under RF power in BAW SMR and its predictive 1D thermal model

This paper intends to provide a contribution for a better understanding of the self-heating effect in BAW SMR by developing a predictive 1D-model. Knowing the power dissipated inside the SMR, the presented model allows us estimating the temperature distribution inside the different layers of resonators used to build BAW filters. Model is compared with both experimental measurements and Finite Elements Analysis. Conclusions concerning the device reliability can eventually be drawn.

Improvement of Capacitive Behavior on Gradient-Free PZT Thin Films

PbZr0,52Ti0,48O3 thin films were synthetized by sol-gel techniques on large scale Pt(111)/TiOx/SiO2/Si substrates (200 mm in diameter). The Zr/Ti ratio gradient – that appears through the thickness of the layer with standard processing – can be reduced using an optimized “gradient-compensated” approach. Capacitance measurements revealed an augmentation of the effective permittivity from 5 to 15% using “gradient-free” PZT (reaching 1700 for 2μm). Large scale breakdown voltage analysis revealed an increase of 20% for the breakdown field for low thicknesses (1.25MV/cm for 240 nm-thick layer) suitable for capacitor integration.