We are developing a hybrid magnetometer based on a doped Si Hall device and a high Tc superconducting flux concentrator. An overview of the present status of the various aspects of research is given. This includes a theoretical derivation of the expected device properties and an optimal design of the concentrator which shows that in theory a sensitivity of 23 V T−1 can be obtained at T = 77 K with an As doped Si Hall device. Moreover, the sensitivity is enhanced by a factor of 10–25, depending on the desired dynamic range, by the concentrator. Implantation of As in Si and pulsed laser deposition of YBa2Cu3O7−δ on Si are the two main challenging production steps which will be discussed in more detail.