| 摘要 |
PURPOSE:To facilitate the integration of both elements, by using a high purity layer for InGaAs, which is to become a light sensitive layer, using an InP layer for a multiplying layer, and using an InAlAs layer between both layers, in an avalanche photodiode; and employing a field effect transistor, which is formed at an InAlAs/InGaAs interface, for an amplifying element; so that many parts of a semiconductor layer are commonly used. CONSTITUTION:Pairs of electrons and holes are generated in a first semiconductor layer 12 with incident light. Owing to an internal electric field, the electrons move in the direction of a substrate 11 and the holes move in the direction of a P-type InP layer 16. Avalanche multiplication of the holes occur owing to the avalanche phenomenon by a high electric field, which is formed in an N-type InP layer 15. InAlAs layers 13 and 14 reduce a barrier for the movement of the holes from a light absorbing InGaAs light sensitive layer 12 to the InP from a light absorbing InGaAs light sensitive layer 12 to the InP multiplying layer 15. Thus the accumulation of the holes is suppressed and the high-speed operation can be performed. The change in potential at a load resistance with the output current of an ava lanche photodiode is applied to a gate electrode 18 of a field effect TRS. The potential is increased with the incident light, and the potential on the side of semiconductors 13' and 14' is decreased. Therefore, a recess at the interface between the layer 12 and 13' becomes large and the amount of an electron gas layer is increased. Thus the output current of the field TRS is increased.
|
