Jacques Faguet

Novel dielectric deposition technology for advanced interconnect with air gap

A Filament-Assisted Chemical Vapor Deposition (FACVD) concept for back-end-of-line (BEOL) applications is presented. Key capabilities of this technology include low-temperature plasma-free film deposition with straightforward scalability and extendibility. Deposition mechanism and film properties are compared with conventional plasma-enhanced CVD (PECVD). FACVD deposition of a decomposable polymer and a porous low-k organosilicate cap is demonstrated to build air gap structures. Other FACVD applications are also discussed.

Elucidating the Mechanisms of Two Unique Phenomena Governed by Particle-Particle Interaction under DEP: Tumbling Motion of Pearl Chains and Alignment of Ellipsoidal Particles

Particle-particle interaction plays a crucial role in determining the movement and alignment of particles under dielectrophoresis (DEP). Previous research efforts focus on studying the mechanism governing the alignment of spherical particles with similar sizes in a static condition. Different approaches have been developed to simulate the alignment process of a given number of particles from several up to thousands depending on the applicability of the approaches. However, restricted by the simplification of electric field distribution and use of identical spherical particles, not much new understanding has been gained apart from the most common phenomenon of pearl chain formation. To enhance the understanding of particle-particle interaction, the movement of pearl chains under DEP in a flow condition was studied and a new type of tumbling motion with unknown mechanism was observed. For interactions among non-spherical particles, some preceding works have been done to simulate the alignment of ellipsoidal particles. Yet the modeling results do not match experimental observations. In this paper, the authors applied the newly developed volumetric polarization and integration (VPI) method to elucidate the underlying mechanism for the newly observed movement of pearl chains under DEP in a flow condition and explain the alignment patterns of ellipsoidal particles. The modeling results show satisfactory agreement with experimental observations, which proves the strength of the VPI method in explaining complicated DEP phenomena.

Elucidating the mechanism governing cell rotation under DEP using the volumetric polarization and integration method

Cell rotation can be achieved by utilizing rotating electric fields through which torques are generated due to phase difference between the dipole moment of cells and the external electric field. While reports of cell rotation under non-rotating electrical fields, such as dielectrophoresis (DEP), are abound, the underlying mechanism is not fully understood. Because of this, contradicting arguments remain regarding if a single cell can rotate under conventional DEP. What’s more, the current prevailing DEP theory is not adequate for identifying the cause for such disagreements. In this work we applied our recently developed Volumetric Polarization and Integration (VPI) method to investigate the possible causes for cell rotation under conventional DEP. Three-dimensional (3D) computer models dealing with a cell in a DEP environment were developed to quantify the force and torque imparted on the cell by the external DEP field using COMSOL Multiphysics software. Modeling results suggest that eccentric inclusions with low conductivity inside the cell will generate torques (either in clockwise or counter-clockwise directions) sufficient to cause cell rotation under DEP. For validation of modeling predictions, experiments with rat adipose stem cells containing large lipid droplets were conducted. Good agreement between our modeling and experimental results suggests that the VPI method is powerful in elucidating the underlying mechanisms governing the complicated DEP phenomena.