Silicon sensors which are capable of detecting the two in-plane components of magnetic field, as well as all three components of the magnetic field vector, are presented. The devices under consideration are based on integrating a Hall plate within a silicon substrate. The sensors have been fabricated in both an n-substrate and a p-well using a commercially available standard CMOS process. The results for the two-dimensional magnetic field sensors exhibit a linear response to an applied field and therefore provides the impetus for the development of a 3-D sensor structure.