Abstract: An N-InP buffer layer is deposited on an N.sup.+ -InP substrate, an InGaAs light-absorbing layer is deposited on the buffer layer, an N.sup.- -InP cap layer is deposited on the light-absorbing layer, and a P-type impurity region is formed in the light-absorbing layer and the cap layer. Next, a masking film is formed on the cap layer, and with this masking film serving as a mask, the cap layer, the light-absorbing layer, the buffer layer are etched, thus forming a P-type electrode forming region and an N-type electrode forming region. Next, an insulating film is provided for the periphery portion of the P-type impurity region of the cap layer. Electrode pads having a laminated structure is formed respectively on the P-type and N-type electrode forming regions, and a non-metal member is formed on the insulating film and on the surface, the periphery and the side surface of the electrode pad of the P-type electrode.

Abstract: An n.sup.- -type InP buffer layer is formed on an n-type InP substrate. An n.sup.- -type InGaAs light absorbing layer is formed on the n.sup.- -type InP buffer layer. An n.sup.- -type InP cap layer is formed on the n.sup.- -type InGaAs light absorbing layer. A p-type InP region is formed in the InP cap layer. A layered electrode having a contact with the p-type InP region comprises a first layer made of an Au layer, a second layer made of a Ti layer or the like, a third layer made of a Pt layer or the like, and a fourth layer made of an Au layer. The first layer made of Au has a thickness of 1 to 500 nm. This structure improves an ohmic ability and a peel strength at a contact portion where an electrode is connected, and simplifies manufacturing steps.