| 摘要 |
PURPOSE:To extend a depletion layer up to a low-concentration semiconductor substrate, and to widen a light-receiving area without increasing junction capacitance by forming a mesa section in low concentration onto the low-concentration semiconductor substrate, forming a Schottky junction on the surface of the mesa section and applying reverse bias. CONSTITUTION:When negative voltage is applied to an anode electrode 4 and positive voltage to cathode electrodes 7 and reverse bias is applied to a Schottky junction 5, a depletion layer 8 extends up to the whole region of a GaAs layer 3 as a mesa section and a GaAs layer 2 from the Schottky junction 5 because impurity concentration in both the GaAs layer 2 and the GaAs layer 3 is low, and where the depletion layer 8 extends constitutes a light-receiving section as a photodiode. Since there is the junction only on the interface between the GaAs layer 3 and anode electrode 4 of the mesa section, on the other hand, the junction capacitance does not inrease though the area of the light-receiving section expands, and the photodiode, which operates at high speed while having high photocurrents, can be obtained. |
