A semiconductor magnetic field sensor comprising a semiconductor well on top of a substrate layer is disclosed. The semiconductor well includes a first current collecting region and a second current collecting region and a current emitting region placed between the first current collecting region and the second current collecting region. The semiconductor well also includes a first MOS structure, having a first gate terminal, located between the first current collecting region and the current emitting region and a second MOS structure, having a second gate terminal, located between the current emitting region and the second current collecting region. In operation, the first gate terminal and the second gate terminal are biased for increasing a deflection length of a first current and of a second current. The deflection length is perpendicular to a plane defined by a surface of the semiconductor magnetic field sensor and parallel to a magnetic field.