P17 - Laser-based method for the fabrication of monolithically and vertically integrated MEMS sensors
- Event
- 22. GMA/ITG-Fachtagung Sensoren und Messsysteme 2024
2024-06-11 - 2024-06-12
Nürnberg - Band
- Poster
- Chapter
- Poster
- Author(s)
- T. Fraunhofer ILT - Aachen
- Pages
- 486 - 491
- DOI
- 10.5162/sensoren2024/P17
- ISBN
- 978-3-910600-01-0
- Price
- free
Abstract
An obstacle to further miniaturization and precision of MEMS sensors is the separate construction of the sensor and the evaluation chip. By integrating the sensor directly onto the ASIC, not only can this source of error be eliminated, but also the space requirement is reduced. One challenge to be addressed is the thermal load of the ASIC, which must not be exceeded. A solution to this problem involves depositing silicon for the sensor structures in an amorphous phase using gas phase deposition. Subsequently, laser radiation is used to crystallize the silicon, and the silicon layer is made conductive by incorporating dopant atoms deposited together with the silicon. Complete crystallization of this layer is crucial for the usability of the MEMS structures for sensors. In this context, strategies for achieving complete crystallization of an amorphous silicon layer are developed, and the complete solid-phase crystallization of a 10 μm thick amorphous silicon layer is demonstrated. This is done experimentally and through FEM simulation. Furthermore, a trade-off between the complete crystallization of the silicon layer and the functional integrity of the ASIC is identified. This trade-off must be experimentally verified and, if necessary, circumvented through appropriate processing strategies.