Low-loss amorphous silicon waveguides grown by PECVD on indium tin oxide

S. Rao; F. G. Della Corte; C. Summonte

doi:10.2971/jeos.2010.10039s

Journal of the European Optical Society - Rapid publications, Vol 5 (2010)

Low-loss amorphous silicon waveguides grown by PECVD on indium tin oxide

S. Rao, F. G. Della Corte, C. Summonte

Abstract

Low-loss hydrogenated amorphous silicon (Î±-Si:H) waveguides were realized by plasma enhanced chemical vapour deposition (PECVD) on a transparent conductive oxide (TCO) layer which is intended to provide the buried contact for the application of an external bias in active devices, e.g. switches and modulators. In particular we propose a technological solution to overcome both the strong reduction in optical transmittance due to the very high extinction coefficient of metal contacts and, at the same time, the optical scattering induced by the texturization effect induced in Î±-Si:H films grown on TCO. The very high optical propagation losses were minimized by depositing a spin-on-glass (SOG) layer between the Î±-Si:H core-layer and the TCO bottom contact. In this case, propagation losses of 2.5 dB/cm at 1550 nm were measured. All the fabricated samples were optically characterized and the surface roughness was accurately measured using a mechanical profilometer. We observed that, for an Î±-Si:H core-layer directly deposited on the TCO contact, the surface roughness is of the order of 100 nm leading to totally opaque waveguides. The experimental performances have been compared to those obtained through calculations using an optical simulation package. The results are found to be in agreement with the experimental data.

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References

G. T. Reed, and A. P. Knights, Silicon Photonics: An Introduction (John Wiley & Sons, New York, 2004).

A. Liu, R. Jones, L. Liao, D. Samara-Rubio, D. Rubin, O. Cohen, R. Nicolaescu, and M. Paniccia, "A high-speed optical modulator based on a metal-oxide-semiconductor capacitor" Nature 427, 615- 618 (2004).

D. Marris-Morini, X. Le Roux, L. Vivien, E. Cassan, D. Pascal, M. Halbwax, S. Maine, S. Laval, J. M. Fédéli, and J. F. Damlencourt, "Optical modulation by carrier depletion in a silicon PIN diode" Opt. Express 14, 10838-10843 (2006).

S. M. Weiss, H. Ouyang, J. Zhang, and P. M. Fauchet, "Electrical and thermal modulation of silicon photonic bandgap microcavities containing liquid crystals" Opt. Express 13, 1090-1097 (2005).

S. E. Holland, N. W. Wang, and W. W. Moses, "Development of low noise, back-side illuminated silicon photodiode arrays" IEEE T. Nucl. Sci. 44, 443-447 (1997).

B. Shi, P. S. Chang, K. Sun, Y. Xie, C. Radhakrishnan, and H. G. Monbouquette, "Monolithic integrated modulator on silicon for optical interconnects" IEEE Photonic. Tech. L. 19, 55-57 (2007).

J. F. Du, X. F. Gu, X. F. Huang, J. Zhou, K. J. Chen, H. Chen, J. H. Yang, and B. C. Cao, "Hydrogenated amorphous silicon PIN photodiode for optically addressed spatial light modulators" in Proceedings to the 4th International Solid-State and Integrated Circuit Technology, 733-735 (IEEE, Beijing, 1995).

F. G. Della Corte, S. Rao, M. A. Nigro, F. Suriano, and C. Summonte, "Electro-optically induced absorption in a-Si:H/a-SiCN waveguiding multistacks" Opt. Express 16, 7540-7550 (2008).

M. A. Green, "Thin-film solar cells: review of materials, technologies and commercial status" J. Mater. Sci. 18, 15-19 (2007).

B. G. Lewis, and D. C. Paine, "Applications and processing of transparent conducting oxides" MRS Bull. 25, 22-27 (2000).

S. Diplas, A. Ulyashin, K. Maknys, A. E. Gunnaes, S. Jørgensen, D. Wright, J. F. Watts, A. Olsen, and T. G. Finstad, "On the processing-structure-property relationship of ITO layers deposited on crystalline and amorphous Si" Thin Solid Films 515, 8539-8543 (2007).

R. A. Synowicki, "Spectroscopic ellipsometry characterization of indium tin oxide film microstructure and optical constants" Thin Solid Films 313, 394-397 (1998).

G. Cocorullo, F. G. Della Corte, R. De Rosa, I. Rendina, A. Rubino, and E. Terzini, "Amorphous silicon-based guided-wave passive and active devices for silicon integrated optoelectronics" IEEE J. Sel. Top. Quant. 4, 997-1002 (1998).

S. K. Selvaraja, E. Sleeck, M. Schaekers, W. Bogaerts, D. V. Thourhout, P. Dumon, and R. Baets, "Low-loss amorphous silicon-on-insulator technology for photonic integrated circuitry" Opt. Commun. 282, 1767-1770 (2009).

A. Harke, M. Krause, and J. Mueller, "Low-loss singlemode amorphous silicon waveguides" Electron. Lett. 41, 1377-1379 (2005).

M. J. A. de Dood, A. Polman, T. Zijlstra, and E. W. J. M. van der Drift, "Amorphous silicon waveguides for microphotonics" J. Appl. Phys. 92, 649-653 (2002).

J. M. Fedeli, L. Di Cioccio, D. Marris-Morini, L. Vivien, R. Orobtchouk, P. Rojo-Romeo, C. Seassald, and F. Mandorlo, "Development of silicon photonics devices using microelectronic tools for the integration on top of a CMOS wafer" Adv. Opt. Technol. 2008, 412518 (2008).

G. Cocorullo, F. G. Della Corte, R. De Rosa, I. Rendina, C. Minarini, A. Rubino, and E. Terzini, "Amorphous silicon waveguides and light modulators for integrated photonics realized by low-temperature plasma enhanced chemical-vapor deposition" Opt. Lett. 21, 2002- 2004 (1996).

M. Iodice, G. Mazzi, and L. Sirleto, "Thermo-optical static and dynamic analysis of a digital optical switch based on amorphous silicon waveguide" Opt. Express 14, 5266-5278 (2006).

J. Lan, and J. Kanicki, "ITO surface ball formation induced by atomic hydrogen in PECVD and HW-CVD tools" Thin Solid Films 304, 123- 129 (1997).

R. Banerjee, S. Ray, N. Basu, A. K. Batabyal, and A. K. Barua, "Degradation of tin-doped indium-oxide film in hydrogen and argon plasma" J. Appl. Phys. 62, 912-916 (1987).

K. K. Lee, D. R. Lim, and L. C. Kimerling, "Fabrication of ultralowloss Si/SiO waveguides by roughness reduction" Opt. Lett. 26, 1888-1890 (2001).

P. Dumon, W. Bogaerts, J. van Campenhout, V. Wiaux, J. Wouters, S. Beckx, and R. Baets, "Low-loss photonic wires and compact ring resonators in silicon-on-insulator" in Proceedings to 2003 IEEE/LEOS Symposium Benelux Chapter, 5-8 (IEEE, Twente, 2003).

S. Kumar, and B. Drevillon, "A real time ellipsometry study of the growth of amorphous silicon on transparent conducting oxides" J. Appl. Physics 65, 3023-3034 (1989).

L. Meng, A. Maqarico, and R. Martins, "Study of annealed indium tin oxide films prepared by RF reactive magnetron sputtering" Vacuum 46, 673-680 (1995).

M. G. Zebaze Kana, E. Centurioni, D. Iencinella, and C. Summonte, "Influence of the sputtering system's vacuum level on the properties of indium tin oxide films" Thin Solid Films 500, 203-208 (2006).

E. Centurioni, "Generalized matrix method for calculation of internal light energy flux in mixed coherent and incoherent multilayers" Appl. Opt. 44, 7532-7539 (2005).

D. G. Stearns, D. P. Gaines, and D. W. Sweeney, "Nonspecular x-ray scattering in a multilayer-coated imaging system" J. Appl. Phys 84, 1003-1028 (1998).

G. Cancellieri, and U. Ravaioli, Measurements of Optical Fibers and Devices: Theory and Experiments (Artech House, Dedham, 1984).

RSoft Photonics CAD Layout User Guide (RSoft Design Group, Ossining).

W. B. Jackson, N. M. Amer, A. C. Boccara, and D. Fournier, "Photothermal deflection spectroscopy and detection" Appl. Opt. 20, 1333-1344 (1981).

S. P. Chan, C. E. Png, S. T. Lim, G. T. Reed, and V. M. N. Passaro, "Single-mode and polarization-independent silicon-on-insulator waveguides with small cross section" J. Lightwave Technol. 23, 2103-2111 (2005).

R. A. Soref, "Silicon-based optoelectronics" P. IEEE 81, 1687-1706 (1993).