Ultrathin, high-sensitivity piezoresistive cantilevers were constructed using vapor-phase epitaxy to grow the conducting layer. A fourfold reduction in thickness was achieved over the thinnest implanted piezoresistive cantilevers, allowing improved force or displacement sensitivity and increased bandwidth. In cantilevers 890 Å thick, the dopant is well confined to the surface, and the sensitivity is 70% of the theoretical maximum. A cantilever fabricated for high force resolution has a minimum detectable force of 8.6 fN/
in air. Additionally, the 1/f
noise is shown to follow the relation proposed by Hooge [Phys. Lett A 29
, 139 (1969)], increasing in inverse proportion to the number of carriers. © 1999 American Institute of Physics.