The surface morphology of (100) n-InP samples photoelectrochemically etched in homogeneous white light was studied. The photoelectrochemical etches were strongly anisotropic and resulted in the production of microstructures, the size and shape of which depended on the charge density and applied potential, respectively At more positive etching potentials V-grooves aligned along the [0 (1) over bar 1] axis were formed, delineated by the (111) and (1<(11)over bar>) indium etch stop planes, whereas etching at more negative potentials resulted in the formation of rectangular shaped pits oriented along the [011] axis. These pits were composed of large (111) and (1<(11)over bar>) indium etch stop planes and a more complex stepped structure which was analyzed in detail. We explain the relationship between the etching potential and the resulting structures by calculating the distribution of photogenerated minority carriers in the region below the surface of the semiconductor.