| 摘要 |
PURPOSE:To obtain a germanium avalanche photodiode which incorporates high quantum efficiency and low noise amplification by forming a part for detecting a light with a high density n type layer, a low density n type layer and a p type layer which forms junction detecting the low density n type layer and light. CONSTITUTION:A part for detecting a light is formed of a high density n type layer 1, a low density n type layer 14 and a p type layer 2 forming a junction 8 for detecting the low density n type layer 14 and the light along the incident light 7. For example, there are formed the high density layer 1 having 10<19>-10<20>/cm<3> of impurity density and 0.3-0.4mum of thickness, the layer 14 having 10<17>/cm<3> of impurity density and sequentially reducing in density in depth direction with a thickness of 2-3mum, the layer 3 of guard ring, and the layer 6 of preventing reflection of the light. A reverse voltage is applied to the junction 8 through the electrodes 4, 5 forming ohmic contact with the layers 1 and 2 respectively in operation. |
