PURPOSE: To suppress one characteristic of a Hall element, i.e., increase of imbalance ratio, while restraining the leak current significantly by setting the product of the carrier concentration and the thickness of a magnetosensitive layer higher than that of a buffer layer.

CONSTITUTION: A heterojunction is formed of GaInAs and AlInAs. Too thick GaInAs layer 103 causes increase of imbalance ratio which is one of the characteristics of a Hall element. Resist material is then removed only from the region for forming a pair of input electrode and output electrode 107 thus exposing the surface of the GaInAs layer 103. Silicon oxide (SiO2) is then deposited except the I/O electrode. In the novel GaInAs Hall element, the leak current is decreased by a factor of ten or more to the order of several hundreds pA to several nA when a voltage of 10V is applied between closest input terminals. Imbalance ratio is also decreased in such Hall element.