Abstract
This paper reports on the modeling and experimental investigation of optical excitation of silicon cantilevers.
In this work, the silicon cantilevers fabricated have dimensions with width of 15 μm, thickness of 0.26 μm,
and variable length from 50 to 120 μm. In order to investigate the effect of the laser modulation frequency
and position on the temperature at the anchor edge and displacements at the tip of cantilevers, a transient
thermal ANSYS simulation and a steady-state static thermal mechanical ANSYS simulation were undertaken
using a structure consisting of silicon device layer, SiO2 sacrificial layer and silicon substrate. The dynamic
properties of silicon cantilevers were undertaken by a series of experiments. The period optical driving signal
with controlled modulation amplitude was provided by a 405 nm diode laser with a 2.9 μW/μm2 laser power
and variable frequencies. The laser spot was located through the longitude direction of silicon cantilevers. In
factor, simulation results well matched with experimental observation, including: 1) for untreated silicon
cantilevers, the maximum of displacement is observed when the laser beam was located half a diameter way
from the anchor on the silicon suspended cantilever side; 2) for the both cantilevers, maximum displacement
occurs when the optical actuation frequency is equal to the resonant frequency of cantilevers. Understanding
the optical excitation on silicon cantilevers, as waveguides, can potentially increase sensing detection
sensitivity (ratio of transmission to cantilever deflection).
