CabTuRes
ENABLING AUTONOMOUS SENSOR NODES: LOW-POWER NANOSENSOR/ELECTRONICS BUILDING BLOCKS BASED ON TUNABLE CARBON NANOTUBE ELECTRO-MECHANICAL RESONATORS
Prof. Christofer Hierold, ETHZ
Prof. Wanda Andreoni, Dr. Danick Briand, EPFL EPFL
Prof. Nico de Rooij, EPFL
Prof. László Forró, EPFL
Dr. Oliver Gröning, EMPA
Prof. Adrian Ionescu, EPFL
Prof. Maher Kayal, EPFL
Prof. Bradley Nelson, ETHZ
Prof. Dimos Poulikakos, Dr. Cosmin Roman, ETHZ ETHZ
What it’s about… Developing nano-mechanical resonators for sensing and electronics applications Context and project goals The project’s goal was to demonstrate concepts and devices for ultra-low power, highly miniaturized functional blocks for sensing and electronics. At the core are carbon nanotube mechanical resonators, which can be tuned via straining over a wide frequency range, offer an unprecedented sensitivity to strain or mass loading, and all these with a very low power consumption. How the project differentiates from similar competition in the field While several research groups worldwide are currently investigating tunable carbon nanotube resonators, CabTuRes distinguishes in its objectives by including fabrication and system integration aspects. System integration is a core task aiming at proving the feasibility of assembling the resonators with interface electronics. Quick summary of the project status and key results CabTuRes has advanced the international state-of-the-art at both the fundamental and technological levels. Regarding technology, processes for growing CNTs with excellent control over location, growth yield and directionality have been demonstrated. Two processes suitable for batch fabrication of CNT resonators have been developed; one focusing on tubes with close-by gates without mechanical straining option; the other focusing on tubes with mechanical actuators for frequency tuning. Tunable CNT resonators have been fabricated and frequency and Q-factor tuning has been demonstrated. Several key blocks of the interface electronics have been designed and characterized, such as a low noise front-end amplifier to interface the CNT devices and a CMOS IC for closed-loop operation of resonators and tested with a CNT emulator. A system integration and packaging process has been defined and most of its critical unit processes—including RF-compatible, ohmic Trough-Silicon-Vias, glass-cap encapsulation and CMOS IC stud-bump soldering—have been developed and tested. At the basic level, the team has investigated adsorption of different chemical species on CNTs and the mechanical interface between CNTs and their anchors.