MEMS Shock Absorbers Integrated with Al2O3-Reinforced, Mechanically Resilient Nanotube Arrays

This paper presents MEMS-integrated nanotube arrays as an in-plane shock absorber to ensure device reliability to external mechanical shocks. The geometrically structured nanotube arrays, consisting of vertically-aligned carbon nanotubes (CNTs) coated with alumina (Al
2
O
3
) layer, are directly integrated onto designated areas, allowing them to be compatible with conventional batch-fabrication processes for MEMS. The deformable carbon nanotube arrays with an exceptionally high aspect ratio dissipate the abruptly applied kinetic energy, while the reinforcing Al
2
O
3
layer provides outstanding mechanical resilience to withstand extreme deformations. Therefore, in the shock-drop test, specimens with the nanotube arrays showed approximately 115 % and 80 % higher survival rate (with an average fracture acceleration of 10,000 g) compared to control groups (without the nanotubes) with a hard stop and compliant spring-based shock absorbers, respectively.