Poly-SiGe for MEMS-above-CMOS Sensors (Springer Series in Advanced Microelectronics, 44)

Acknowledgements. Abstract. Symbols and Abbreviations.

1 Introduction. 1.1 Motivation and goal of this work. 1.2 MEMS: definition, technologies and applications. 1.3 CMOS-MEMS integration: why, how and what? 1.4 Polycrystalline SiGe for MEMS-above-CMOS applications. 1.5 A poly-SiGe based MEMS pressure sensor. 1.6 Outline of the book.

2 Poly-SiGe As Piezoresistive Material. 2.1 Introduction to piezoresistivity. 2.2 Sample preparation. 2.3 Measurement setup. 2.4 Results and discussion. 2.5 Summary and conclusions.

3 Design of a Poly-SiGe Piezoresistive Pressure Sensor. 3.1 A piezoresistive pressure sensor: definition and important performance parameters. 3.2 Design. 3.3 Summary and conclusions of the sensor design.

4 The Pressure Sensor Fabrication Process. 4.1 The pressure sensor fabrication process: a generic technology. 4.2 Pressure sensor schematic process flow. 4.3 Process developments and challenges. 4.4 Discussion on the poly-SiGe pressure sensor process.

5 Sealing of Surface Micromachined Poly-SiGe Cavities. 5.1 Introduction. 5.2 Fabrication process. 5.3 Direct sealing. 5.4 Intermediate porous cover. 5.5 Measurement setup. 5.6 Analytical model. 5.7 Results and discussion. 5.8 Summary and conclusion.

6 Characterization of Poly-SiGe pressure sensors. 6.1 Measurement setup. 6.2 Measurement results: pressure response. 6.3 Summary and conclusions. 6.4 Capacitive pressure sensors.

7 CMOS Integrated Poly-SiGe Piezoresistive Pressure Sensor. 7.1 The sensor readout circuit: an instrumentation amplifier. 7.2 Fabrication of a CMOS integrated pressure sensor. 7.3 Effect of the MEMS processing on CMOS. 7.4 Evaluation of the CMOS-integrated pressure sensor. 7.5 Conclusions.

8 Conclusions And Future Work. 8.1 Conclusions and contribution of the dissertation. 8.2 Future research directions and recommendations.

Appendix A. Appendix B. Appendix C. Appendix D.

Pilar González Ruiz received her M.S. degree in Electrical Engineering from the University of Sevilla, Spain, in 2006. She obtained the PhD degree from the Electrical Engineering Department (ESAT) at the University of Leuven, Belgium in 2012. During her PhD she worked on the integration of MEMS and CMOS using polycrystalline silicon-germanium, with a focus on pressure sensors, at imec, Leuven, Belgium. Since 2012 she has been working on integrated imagers at imec, Leuven, Belgium. She has authored or co-authored more than 10 technical papers for publication in journals and presentations at conferences and holds various patents.

Kristin De Meyer M.Sc. (1974), PhD (1979) KULeuven. She was holder of an IBM World Trade Postdoctoral Fellowship at the IBM T. J. Watson Research Center, Yorktown Heights, NY. Currently she is the Director of Doctoral Research in imec. Since October 1986, she has also been a Part-Time Professor with ESAT-INSYS, KUL. She was the Coordinator for IMEC in several EEC projects. Dr. De Meyer is an IIEE fellow, member of the Belgian Federal Council for Science Policy and (co) author of over 500 publications.

Ann Witvrouw received an MS degree in Metallurgical Engineering in 1986 from the Katholieke Universiteit Leuven, Belgium, and both an MS degree in Applied Physics in 1987 and a Ph.D. degree in Applied Physics in 1992 from Harvard University, USA. In 1992 she joined imec, Belgium where she worked on the reliability of metal interconnects until the end of 1998. In 1998 she switched to research in Micro-electromechanical Systems at imec, focusing on advanced MEMS process technologies. From 2000 to 2013 she has been working on MEMS integration at imec, first as team leader, then as a program manager and last as a principal scientist. Currently she is a guest professor at the KULeuven, teaching part of a course on 'Nanomaterials for nanoelectronics'.