JPS6259895B

PURPOSE:To obtain a multi-wavelength light beam sensing element of the monolithic structure by stacking semiconductor layers in different compositions for epitaxial growth on a compound semiconductor substrate, forming the surface like a staircase by etching, using this surface as the light sensible area and providing opposing electrodes to both ends thereof. CONSTITUTION:The In0.79Ga0.21As0.45P0.55 layer 17, In0.67Ga0.33As0.71P0.29 layer 18 and In0.53Ga0.47AsP layer 19 are stacked on an InP substrate 16, allowing epitaxial growth thereof and these layers are etched into a form of staircase until a part of layers 17-19 is respectively exposed to the surface. The surfaces of layers thus exposed are used as the light sensible surfaces 20-23 and the opposing electrodes 24 and 25 of Au/Sn which is continuous like a staircase are deposited to both ends thereof. Otherwise, it is also possible that these electrodes are divided opposingly and an isolation groove is provided between the respectively light sensible surfaces.