| 摘要 |
PURPOSE:To obtain a high voltage resistance avalanche photodiode by making a circumferential part of a planer-type P-N junction lower in the impurity concentration out farther of the center. CONSTITUTION:N type InGaAs epitaxial layer 2 and N type InP epitaxial layer 3 are deposited on N type InP substrate 1. A layer 4 has the Zn concentration of 10<18>/cc or larrger, and a layer 5 and a layer 6 have the Zn concentration of about 10<17>/cc and 10<16>/cc, respectively. With this construction, the depth of the surrounding impurity concentration region is about corresponding to the position of P-N junction at the center so when a reverse bias is increased, a depletion layer never first reaches an InGaAs layer around the circumference. Further, the P-side depletion layer boundary widens up to the circumferential region, and an electrostatic focusing is reduced. If an impurity layer is deeper for farther from the center, the dielectric strength increases more, and if a double-impurity-layer device is formed at the circumference, the dielectric strength increases yet more. |
