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US 7,095,006 B2Granted
Photodetector with hetero-structure using lateral growth
AssigneeInternational Business Machines Corporation
InventorMin Yang
Life of this patent
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Abstract
A structure and method of fabrication for a Si based material p-i-n photodetector is disclosed. The light is absorbed in an undoped layer containing SiGe or Ge in such a manner that the absorption length is not limited by a critical thickness of the SiGe or Ge layer. The result is achieved by growing the SiGe or Ge layer from the walls of a trench in monocrystalline Si using lateral epitaxial. A second, doped material is disposed over the undoped layer for biasing and photocarrier collection in the p-i-n diode.
Claims13
A photodetector, comprising:
- a monocrystalline Si well of a first conductivity type, wherein said well has a surface plane, and wherein said well contains at least one trench downwardly extending from said surface plane;
- an undoped epitaxial layer lining said at least one trench, wherein said undoped epitaxial layer comprises a Si1−xGex layer with 0<x≦1, wherein said Si1−xGex layer has a thickness which is below a critical thickness, wherein a cross sectional surface of said undoped epitaxial layer forms a band which is substantially aligned with said surface plane;
- and
- a second material of a second conductivity type disposed over said undoped epitaxial layer but not in contact with said band.
1 more element
Dependencies are inferred from the claim text.