MSM-Metal Semiconductor Metal Photo-detector Using Black Silicon Germanium (SiGe) for Extended Wavelength Near Infrared Detection
ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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We have investigated for the first time the electrical properties of metal-semiconductor-metal MSM photodectors fabricated using black silicon-germanium on silicon substrate Si1-xGexSi for I-V, optical response, external quantum efficiency EQE, internal quantum efficiency IQE, and responsivity and reflectivity. Silicon-germanium Si1-xGexSi with variations of Ge were blackened by metal enhanced chemical etching MECE using nanometer-scale gold particles as catalyst and HFH2O2CH3COOH solution as etchant. The etched surface was black, textured, and showed strong suppression of reflectivity. These properties are consistent with Si1xGex becoming highly micro-structured due to metal catalysis and wet etching. Using the blackened SiGeSi, MSM photodiodes were fabricated and tested. The lowering of reflection using a U.S. Army Research Laboratory ARL-developed technique has helped the enhancement of absorption in Si1-xGex to provide increased optical response, which is an important milestone towards practical, extended wavelength 2 microns electro-optical applications.
- Infrared Detection and Detectors