MSc thesis project proposal

[2020] CMOS Monolithic integration of 2D arrays of ultrasound transducers for neuromodulation

Low intensity focused ultrasound is an emerging non-invasive neuromodulation modality combining high depth of penetration in body tissue with high spatial resolution [1]. Stimulation or inhibition of neuronal activity with ultrasound occurs at the focal region, and reducing the volume of this region leads to higher spatial resolution of neuromodulation. This can be achieved by increasing the frequency of the ultrasound frequency and by increasing the total area of the ultrasound transducer, and the long term ambition is to achieve spatial resolution of stimulation comparable to implantable electrodes in a non-invasive way. In addition, to allow for electronic control of the focal region location, 2D arrays of ultrasound transducers need to be fabricated at the micro-scale closely to the driving electronics, which can potentially lead for stimulation of different neuronal circuits, comparable to implantable microelectrode arrays.

The combination of high frequency ultrasound and the need to fabricate transducers closely to the electronics leads to the need to monolithically integrated the ultrasound transducers directly on top of the electronics in a single chip.

The goal of this project is to develop a fabrication and integration method for 2D arrays of piezoelectric transducers directly on top of silicon chips, and will have as a starting point a previously developed prototype and methodology [2].

References:

[1] Tufail, Y. et al. Transcranial pulsed ultrasound stimulates intact brain circuits. Neuron 66, 681–94 (2010).

[2] Shi, C., Costa, T., Elloian, J. & Shepard, K. L., “Monolithic Integration of Micron-scale Piezoelectric Materials with CMOS for Biomedical Applications“ in 2018 IEEE International Electron Devices Meeting (IEDM).

Assignment

1st part: Literature review of ultrasound transducers and integration methods in CMOS devices.

2nd part: Design, fabrication and testing of a 2D array of ultrasound transducers monolithically integrated in a silicon chip for neuromodulation applications.

Requirements

MSc students from Microelectronics, Biomedical Engineering or Mechanical Engineering. Interested students should include their CV, list of courses attended and grades obtained.

Contact

dr. Tiago Costa

Bioelectronics Group

Department of Microelectronics

Last modified: 2021-02-10