50 nm thick AlN film-based piezoelectric cantilevers for gravimetric detection

Abstract

Due to low power operation, intrinsic integrability and compatibility with CMOS processing, aluminum nitride (AlN) piezoelectric (PZE) microcantilevers are a very attractive paradigm for resonant gas sensing. In this paper, we theoretically investigate their ultimate limit of detection and enunciate design rules for performance optimization. The reduction of the AlN layer thickness is found to be critical. We further report the successful development and implementation in cantilever structures with a 50 nm thick active PZE AlN layer. Material characterizations demonstrate that the PZE e 31 coefficient can remain as high as 0.8 C m −2. Electrically transduced frequency responses of the fabricated devices are in good agreement with analytical predictions. Finally, we demonstrate the excellent frequency stability with a 10 −8 minimum Allan deviation. This exceptionally low noise operation allows us to expect a limit of detection as low as 53 zg μm −2 and demonstrate the strong potential of AlN PZE microcantilevers for high resolution gas detection.

Fundamentals of Nanomechanical Resonators

“…In each one of those cases the resulting equations will be different. The three more used types of piezoelectric resonators are: flexural beams and cantilevers [58][59][60][61][62], dilational (thickness) bulk acoustic wave mode [52,55,63] (Fig. 4.16), and lateral contour mode [64][65][66].…”

Comparison of in-plane and out-of-plane piezoelectric microresonators for real-time monitoring of engine oil contamination with diesel

“…It uses a dummy device that duplicates the structure of the resonator, being basically an unreleased copy of the plate, to prevent its vibration. An approximately 1 % of mismatch in capacitance between the cantilever and the dummy has been observed (Ivaldi et al 2011). An instrumentation amplifier (AD8428) subtracts the dummy (v dum ) from the resonator response (v res ).…”

Highly Scalable NEMS Relays With Stress-Tuned Switching Voltage Using Piezoelectric Buckling Actuators

“…For example, for the technology node t = g 0 = 1 nm, V s can be reduced to 10 mV for L = 175 nm (assuming that no leakage or tunneling effects occur at g 0 = 1 nm). Considering the recently reported data on the synthesis of ultrathin (down to 10 nm) AlN piezoelectric films with very high quality [5], [21], [23] and with future progress in thin-film deposition techniques, the demonstration of millivolt switching using this technology can be envisioned. In addition, since the generated piezoelectric stress and so the associated switching voltage is independent on the area of the anchored actuators, their footprints can be drastically scaled to reduce the gate-body capacitance and, consequently, minimize the switching energy.…”