On-chip porous silicon microthruster for robotic platforms

Porous silicon has emerged as a promising on-chip energetic material capable of generating energy that can be harnessed for high force, high displacement actuation on microrobotic platforms. This work provides initial characterization of this microfabricated energetic material with respect to force and specific impulse. Output force from samples with varying pore morphologies is measured with a high bandwidth force sensor. A new microfabrication process is also introduced to provide a cap and nozzle for confined thrust, and output force is compared between confined and unconfined samples. Results demonstrated that a 14% decrease in porosity led to a 4X increase in force output, while the addition of a confining cap improved peak force output by 2X. The case of lower porosity with confinement resulted in a specific impulse of 126 s.