Si Nano-Photodiode with Surface-Plasmon Antenna Junichi FUJIKATA, Keishi OHASHI and Toru MOGAMI We studied the surface plasmon SP resonance effect on Si nano-photodiode PD characteristics for future optical interconnections on LSI chips. We designed an SP antenna which converts input light into SP polaritons and localizes light power on the subwavelength area, and developed a very efficient and very fast Si nano-pd which consists of the SP antenna and a small Si absorption layer. We also developed a waveguide-integrated Si nano-pd with an SP antenna for on-chip optical clock distribution. The interfacial periodic nano-scale metal-semiconductor-metal Schottky electrodes were shown to function as an SP optical antenna and also as an optical coupler between a SiON waveguide and a very thin Siabsorption layer. A very high speed response as well as enhanced photoresponsivity was achieved for a 10-mm coupling length. By using this technology, we fabricated a prototype of a large-scale-integration LSI on-chip optical clock system and demonstrated 5 GHz of optical clock circuit operation connected with a 4-branching H-tree structure. Key words: photodiode, silicon photonics, surface-plasmon, nano-photonics, optical waveguide VLSI Si CMOS complementary metal oxide semiconductor LSI CMOS Si LSI 1 6 Si 7 10 Gbit/s InGaAs avalanche photo diode; APD GaAs pin pin-pd Si CMOS Si 1 305 8501 34 E-mail: j-fujikata@cj.jp.nec.com MIRAI-Selete 305 8501 34 98 32
«hole grating metal 1 a b 8 Si LSI Si 1. 1998 Ebbesen 9 10 11 1944 Bethe aperture theory 12 1 a hole array b 40 2 2011 Incident side Output side 2 a b 2 finite-difference time-domain method; FDTD a b beaming 2. 13 3 Si 3 1 99 33
300 nm SiO 2 n-si n + -Si Ti/Au Ag Cr SiO 2 1 m (c) 3 13 Cr/Ag SiO 2 2 Si 3 Si 1/e 850 nm Si 1 4 SEM Si SEM Si 200 nm Ag 560 nm 50 nm SiO 2 300 nm Si 10 nm Cr SiO 2/Ag 100 34 4 a b SEM c Si SEM 13 5 1.50 10 n eff e m e d/e m e d 1/2 1 n eff e m e d 560 nm 840 nm 5 840 nm 1 mw 2 3 m Si Si
Input light of TM polarization 1.1 m Ag nano-electrode embedded in Si SiON waveguide SiO 2 clad SiON waveguide Si nano-photodiode Optical coupling by nano-scale Ag MSM electrodes 1.0 (c) 300 nm 200 nm 0.1 ff 10 7 cm/s ps 80 GHz 3. 14 LSI LSI SiON 15 18 Si Si 6 a Ag MSM metal-semiconductor-metal FDTD 240 nm Si 90 nm 30 nm Ag SiON Si 850 nm TM SiON 6 b c SiON Si Ag-MSM SiON vertical mode horizontal mode 40 2 2011 10 m 0.01 6 a Si b c 850 nm TM SiON 14 7 Si 14 85 240 nm Si 7 Si Si Si Ag Si 780 900 nm 60 Si Ag-MSM SEM 8 a b Si n-type SOI silicon-on-insulator 10 mm LOCOS local oxidation of silicon Si EB electron beam Ag-MSM SiON SiO 2 8 c Si 850 nm 1.6 mw SiON 10 TE 2 3 SiON Si 10 mm 4 ff 1 6 101 35
8 a Si b Ag-MSM SEM c 14 9 a b 1V dc c dc 14 4. 14 Si 9 a 1 2 MMI multi-mode interference 2 4 4 Si 9 b c Si 1 V dc dc 780 nm 2 ps 65 GHz Si 1 V 17 ps dc 15 ps Si CMOS 10 a b LSI SEM LSI Cu LSI 10 c Si TIA trans-impedance amplifier 102 36 Optical clock signal input (c) Optical chip 1mm PD PMOS LSI chip Vout (d) SiON WG LSI chip 100mV Si nano-pd Cu via Solder bump 10 m 100ps 10 a LSI b SEM c d 5 GHz LSI 14 10 d 5 GHz LSI 850 nm 4 mw CW 5 GHz 4 LSI VLSI Si-CMOS Si
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