Light-receiving element, light-receiving element array, method for manufacturing light-receiving element and method for manufacturing light-receiving element array

A light-receiving element comprising a group III-V compound semiconductor stacked structure including an absorption layer having a pn-junction therein, the group III-V compound semiconductor stacked structure being formed on a group III-V compound semiconductor substrate,

• wherein the absorption layer has a multiquantum well structure composed of group III-V compound semiconductors, the pn-junction is formed by selectively diffusing an impurity element into the absorption layer,
• a diffusion concentration distribution control layer composed of III-V group semiconductor is disposed in contact with the absorption layer on a side of the absorption layer opposite the side adjacent to the group III-V compound semiconductor substrate,
• the bandgap energy of the diffusion concentration distribution control layer is smaller than that of the group III-V compound semiconductor substrate,
• the concentration of the impurity element selectively diffused in the diffusion concentration distribution control layer is decreased to be 5×1016/cm3 or less toward the absorption layer.

A method for producing a light-receiving element having a group III-V compound semiconductor stacked structure that includes an absorption layer having a pn-junction therein, the method comprising the steps of:

• forming the absorption layer on an InP substrate so as to have a multiquantum well structure;
• forming, on the absorption layer, a diffusion concentration distribution control layer having a bandgap energy smaller than the bandgap energy corresponding to that of InP in order to control the concentration of an impurity element in the absorption layer to be low;
• and
• selectively diffusing the impurity element into the absorption layer through the diffusion concentration distribution control layer to decrease the impurity element in the diffusion concentration distribution control layer to be 5×1016/cm3 or less toward the absorption layer.