A semiconductor element, a semiconductor element preparing method, and a solid state imaging apparatus. The semiconductor element comprises: a group of first modulation grids, a group of second modulation grids, a semiconductor region, a first storage region, and a second storage region. The group of first modulation grids and the group of second modulation grids are respectively provided with different voltages, the potential of a signal charge transfer path in the semiconductor region is changed, and signal charges are controlled to move along a second direction; the first storage region is directly connected to the first modulation grids, so that when the voltage of the first storage region is higher than the voltage of the first modulation grids, and the first storage region attracts first signal charges retained in the first modulation grids.