Micro-Hall sensors made of Bi have been previously fabricated and have shown interesting properties for magnetic field detection. In this project, new ideas to improve the performance of these Hall sensors and to explore ferromagnetic metals are developed. Ni and Bi protected with Al2O3 are used as materials to realize the sensing element. Different thicknesses between 10 and 100 nm of Ni and Bi are deposited by evaporation and structured with lift-off. The electrodes are made of Ti/Al. A Pt thin film is deposited between the sensor and the electrodes to improve electrical contact. Two SU-8 layers are structured with the standard photolithography process to build a cantilever and a carrier chip. Release of the sensor chip is performed with ICP SF6 plasma to etch the poly-Silicon layer.