design and realization of saw pressure sensor using aluminum nitrid

UNIVERSITE JOSEPH FOURIER- GRENOBLE I SCIENCES.TECHNOLOGIE.SANTE N° attribué par la bibliothèque |__|__|__|__|__|__|__|__|__|__| T H E S E pour obtenir le grade de DOCTEUR DE L’UNIVERSITE JOSEPH FOURIER Spécialité : Radio-Fréquence préparée au laboratoire CEA/LETI-Minatec - IMEP-LAHC dans le cadre de l’Ecole Doctorale "Electronique, Electrotechnique, Automatique, Télécommunication, Signal" présentée et soutenue publiquement par Trang HOANG Le 19/01/2009 TITRE Design and realization of SAW pressure sensor using Aluminum Nitride DIRECTEUR DE THESE Philippe BENECH JURY M.Daniel Barbier Président Mme. Hélène Tap-Beteille Rapporteur M. Gilles Despaux Rapporteur M.Patrice Rey Examinateur M.Philippe Robert Examinateur M.Philippe Benech Directeur de thèse [...]... or delay time of SAW sensor Figure 1.9 Environmental influences to the SAW sensors Among these applications, the pressure sensor plays a key part of many systems, both commercial and industrial Our work focuses on this kind of sensor SAW pressure sensors could be divided into two types: + One port IDT, + Two port IDT 1.1.6.1 SAW pressure sensor with one port IDT The SAW pressure sensor using one port... Background Figure 1.11 SAW pressure sensor, one IDT and with external sensor circuit Z 1.1.6.2 SAW pressure sensor with two ports IDT The general structure of the SAW pressure sensor with two ports IDT is illustrated on Figure 1.12 Figure 1.12 General structure of a SAW pressure sensor with two IDTs The signal frequency: f where v is wavelength, v is the phase velocity of a SAW and determined in the... the SAW device From this point of chapter 1, equivalent circuit of SAW device based on Mason model and Coupling -Of- Mode is presented in chapter 2 This chapter also analyses the SAW parameters in different structures of SAW devices (AlN/SiO2/Si, AlN/Si, and AlN/Mo/Si) Chapter 3 gives the development of the model used for SAW pressure sensor and mechanical analysis of the sensitive membrane under pressure. .. Temperature, Pressure, Torque, Mass, Humidity, Vapor Chemical, and Bio sensors Among these sensors, pressure sensor play a key part of many systems, both commercial and industrial SAW pressure sensors have been developed by using many different piezoelectric materials Conventional piezoelectric materials such as quartz, LiNbO3 and LiTaO3 suffer 1 Introduction from a variety of limitations and in particular... at high temperature (up to 10000C) The goal of this thesis is the design and realization of SAW pressure sensor using AlN This kind of device can be used in high temperature applications However, in large range of temperature, properties of materials are affected by temperature variations Therefore, the center frequency is sensible to temperature changes For pressure application, this sensitivity must... track [6] + With external sensor circuit Figure 1.11 shows the diagram of a SAW pressure sensor with one IDT and external sensor circuit represented by its input impedance Z Z could be another pressure sensor When external sensor Z changes due to applied pressure, the reflector parameters will change Consequently, RF response changes also By capturing the variation of RF signal, pressure can be measured... appeared in the field of micro-electronics, pushed by many developments on BAW RF resonators of the type AlN is an attractive material for high-frequency SAW and for many SAW applications due to its good properties, such as outstanding ultrasonic velocity, thermal and chemical stability Beside, its process of deposit compatible with silicon offers new prospects for the realization of sensors and piezoelectric... generate the acoustic wave For application of pressure sensor, the ZnO/Si SAW pressure sensor was studied by A.Talbi [10][13] But, in our work AlN is used as piezoelectric material 1.2 PIEZOELECTRIC MATERIALS ALUMINUM NITRIDE (ALN) AND ITS APPLICATIONS IN SAW DEVICES 1.2.1 Piezoelectric materials and the choice of AlN Piezoelectricity, discovered by brothers Pierre and Paul-Jacques Curie in 1880, received... between calculation and measurement 118 Figure 5.24 Frequency response and Comparison between experiment (high resistance and normal substrate) and simulation .118 Figure 5.25 Comparison between AlN/Mo/Si and AlN/Si SAW devices 119 Figure 5.26 The thickness of Mo and AlN-dependence of wave velocity 120 Figure 5.27 The thickness of Mo and AlN-dependence of coupling factor... combination of the elastic constant cikjm, and depends on the cut of the substrate; is the mass density of the wave guiding layer of the substrate For the multi-layers structure, the SAW velocity could be determined by the matrix method developed by Fahmy and Adler [69], [69], [70] and it also depends on the elastic constants of each layer The applied pressure will induce static stress and strain and modify . goal of this thesis is the design of a surface acoustic wave (SAW) pressure sensor using Aluminium Nitride (AlN). Theoretical studies, realization, and characterization of the pressure sensor. Comparation between four sensors 11 1.1.6 SAW sensor and the application pressure sensor in this research 12 1.1.6.1 SAW pressure sensor with one port IDT 13 1.1.6.2 SAW pressure sensor with two ports. 1.10 SAW wireless pressure sensor with one broadband reflective delay line 14 Figure 1.11 SAW pressure sensor, one IDT and with external sensor circuit Z 15 Figure 1.12 General structure of a SAW