Integration of germanium waveguide photodetectors for intrachip optical interconnects

The main characteristics of germanium photodetectors integrated in silicon-on-insulator optical waveguides for intrachip optical interconnects are presented. The epitaxial Ge layers are grown on Si(001) by reduced-pressure chemical vapor deposition. The optical absorption of Ge layers is recorded from 1.2 to 1.7 µm and linked to the layer strain. The responsivity of an interdigitated metal-semiconductor-metal Ge photodetector has been measured. Light coupling from a slightly etched submicron rib silicon-on-insulator waveguide to a Ge photodetector is studied for two configurations: butt coupling and vertical coupling.

[1]  R. Newman,et al.  Intrinsic Optical Absorption in Single-Crystal Germanium and Silicon at 77°K and 300°K , 1955 .

[2]  D. C. Northrop,et al.  Metal-germanium Schottky barriers , 1973 .

[3]  J.C. Campbell,et al.  Metal-germanium-metal photodetectors on heteroepitaxial Ge-on-Si with amorphous Ge Schottky barrier enhancement layers , 2004, IEEE Photonics Technology Letters.

[4]  Thomas A. Langdo,et al.  Controlling threading dislocation densities in Ge on Si using graded SiGe layers and chemical-mechanical polishing , 1998 .

[5]  Philippe Dollfus,et al.  Band offset predictions for strained group IV alloys: Si1-x-yGexCy on Si(001) and Si1-xGex on Si1-zGez(001) , 2000 .

[6]  Yves Campidelli,et al.  Near-infrared waveguide photodetector with Ge/Si self-assembled quantum dots , 2002 .

[7]  Maria Eloisa Castagna,et al.  Si-based materials and devices for light emission in silicon , 2003 .

[8]  M. Paniccia,et al.  A high-speed silicon optical modulator based on a metal–oxide–semiconductor capacitor , 2004, Nature.

[9]  D. Miller,et al.  Optical interconnects to silicon , 2000, IEEE Journal of Selected Topics in Quantum Electronics.

[10]  R. Bechmann,et al.  Numerical data and functional relationships in science and technology , 1969 .

[11]  Laurent Vivien,et al.  Reduced pressure–chemical vapor deposition of Ge thick layers on Si(001) for 1.3–1.55-μm photodetection , 2004 .

[12]  Elia Palange,et al.  Metal–semiconductor–metal near-infrared light detector based on epitaxial Ge/Si , 1998 .

[13]  Bahram Jalali,et al.  Optimization of Si/sub 1-x/Ge/sub x//Si waveguide photodetectors operating at /spl lambda/=1.3 /spl mu/m , 1996 .

[14]  A. Koster,et al.  Experimental demonstration of a low-loss optical H-tree distributionusing silicon-on-insulator microwaveguides , 2004 .

[15]  Bahram Jalali,et al.  SOI Waveguide GeSi Avalanche Pin Photodetector at 1.3 æm Wavelength , 1998 .

[16]  A. Sudbø,et al.  Film mode matching: a versatile numerical method for vector mode field calculations in dielectric waveguides , 1993 .

[17]  Van de Walle Cg.  Band lineups and deformation potentials in the model-solid theory. , 1989 .

[18]  Yasuhiko Ishikawa,et al.  Strain-induced band gap shrinkage in Ge grown on Si substrate , 2003 .