A variety of piezoresistive cantilevers.
Here are PDF downloads of my publications from graduate school, and one from Agilent.
Thesis: Advances in Piezoresistive Probes for Atomic Force Microscopy
JMEMS: 1/f Noise Considerations for the Design and Process Optimization of Piezoresistive Cantilevers
APL: High Sensitivity Piezoresistive Cantilevers under 1000 Angstroms Thick
ASME: Design of Resonant Beam Transducers: An Axial Force Probe for Atomic Force Microscopy
Transducers: A High-Performance Dipole Surface Drive for Large Travel and Force