SiGe PHOTODIODE
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Accused Products
Abstract
The lattice mismatching between a Ge layer and a Si layer is as large as about 4%. Thus, when the Ge layer is grown on the Si layer, penetration dislocation is introduced to cause leakage current at the p-i-n junction. Thereby, the photo-detection sensitivity is reduced, and the reliability of the element is also lowered. Further, in the connection with a Si waveguide, there are also problems of the reflection loss due to the difference in refractive index between Si and Ge, and of the absorption loss caused by a metal electrode. In order to solve said problems, according to the present invention, there is provided a vertical type pin-SiGe photodiode having a structure which is embedded in a groove formed in a part of a Si layer, in which a p-type or n-type doped layer is formed in a lower section of the groove, and in which a i-SiGe layer having a rectangular shape or a reverse tapered shape is formed on a layered structure formed by laminating a i-Si layer and a SiGe buffer layer on the lower section and the side wall of the groove. Further, in an optical connection section with a Si waveguide, impedance matching is effected by the layered structure composed of the i-Si layer and the SiGe buffer layer, and an upper metal layer is separated therefrom so that a poly-Si bridge structure is employed to electrically connect the upper metal layer therewith.
102 Citations
16 Claims
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1-7. -7. (canceled)
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8. A SiGe photodiode, which is a p-i-n type photodiode composed of a SixGe1-x semiconductor absorption layer, an upper electrode layer provided on the top face thereof, and a lower electrode layer provided under the rear face thereof,
wherein the p-i-n type photodiode has a structure in which the SixGe1-x semiconductor absorption layer is embedded in a groove formed in a part, of a Si layer, and which comprises: -
a p-type or n-type doped lower electrode layer which is formed in a lower section of the groove; a layered structure composed of, a Si semiconductor layer and a SiGe buffer layer, which structure is formed on the lower section and the side wall of the groove; the SixGe1-x semiconductor absorption layer which is formed on the layered structure; and a n-type or p-type doped upper electrode layer which is formed in an upper section of the groove. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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Specification