Photoinduced and thermal stress in silicon microcantilevers

The photogeneration of free charge carriers in a semiconductor gives rise to mechanical strain. We measured the deflection of silicon microcantilevers resulting from photoinduced stress. The excess charge carriers responsible for the photoinduced stress, were produced via photon irradiation from a diode laser with wavelength lambda = 780 nm. For Si microcantilevers, the photoinduced stress is of opposite direction and about four times larger than the stress resulting from only thermal excitation. In this letter we report on our study of the photoinduced stress in silicon microcantilevers and discuss their temporal and photometric response. (C) 1998 American Institute of Physics. [S0003-6951(98)03742-5].