Abstract

SiGe alloys present a large Infra-Red transparency window and a full compatibility with the standard Complementary Metal Oxide Semiconductor processing making them suitable for applications in integrated optics. In this paper we report on Mlines characterization of Si1-xGex graded index waveguides at 2.15 µm. First, a law giving the refractive index of a Si1-xGex alloy as a function of the Ge content x: n = 1.342x2 + 0.295x + 3.451, has been experimentally established in the 0 < x < 0.4 range. Then, we have demonstrated that our methodology based on Mlines measurements can be used as short-loop non-destructive technique to provide feedback for sample growth.

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References

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    [CrossRef]
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    [CrossRef]
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    [CrossRef] [PubMed]
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2011

2010

2009

2006

R. Soref, S. Emelett, and W. Buchwald, “Silicon waveguided components for the long-wave infrared region,” J. Opt. A: Pure Appl. Opt8(10), 840–848 (2006), http://stacks.iop.org/1464-4258/8/i=10/a=004 .
[CrossRef]

L. Labadie, C. Vigreux-Bercovici, A. Pradel, P. Kern, B. Arezki, and J. E. Broquin, “M-lines characterization of selenide and telluride thick films for mid-infrared interferometry,” Opt. Express14(18), 8459–8469 (2006).
[CrossRef] [PubMed]

2004

Z. Ikoni, R. W. Kelsall, and P. Harrison, “Waveguide design for mid- and far-infrared p-Si/SiGe quantum cascade lasers,” Semicond. Sci. Technol.19(1), 76–81 (2004), http://stacks.iop.org/0268-1242/19/i=1/a=013 .
[CrossRef]

2002

A. V. Khomchenko, “M-lines technique application for studying of optical nonlinearities in thin films at a low light intensity,” Opt. Commun.201, 363–372 (2002), http://www.sciencedirect.com/science/article/pii/S0030401801016832 .

1999

1998

M. Robillard, P. E. Jessop, D. M. Bruce, S. Janz, R. L. Williams, S. Mailhot, H. Lafontaine, S. J. Kovacic, and J. J. Ojha, “Strain-induced birefringence in Si1-xGex optical waveguides,” J. Vac. Sci. Technol. B16(4), 1773–1776 (1998), http://link.aip.org/link/?JVB/16/1773/1 .
[CrossRef]

1990

1970

1969

P. K. Tien, R. Ulrich, and R. J. Martin, “Modes of propagating light waves in thin deposited semiconductor films,” Appl. Phys. Lett.14,291–294 (1969), http://link.aip.org/link/?APL/14/291/1 .

Arezki, B.

Asher, W.

Baehr-Jones, T.

Broquin, J. E.

Bruce, D. M.

M. Robillard, P. E. Jessop, D. M. Bruce, S. Janz, R. L. Williams, S. Mailhot, H. Lafontaine, S. J. Kovacic, and J. J. Ojha, “Strain-induced birefringence in Si1-xGex optical waveguides,” J. Vac. Sci. Technol. B16(4), 1773–1776 (1998), http://link.aip.org/link/?JVB/16/1773/1 .
[CrossRef]

Buchwald, W.

R. Soref, S. Emelett, and W. Buchwald, “Silicon waveguided components for the long-wave infrared region,” J. Opt. A: Pure Appl. Opt8(10), 840–848 (2006), http://stacks.iop.org/1464-4258/8/i=10/a=004 .
[CrossRef]

Emelett, S.

R. Soref, S. Emelett, and W. Buchwald, “Silicon waveguided components for the long-wave infrared region,” J. Opt. A: Pure Appl. Opt8(10), 840–848 (2006), http://stacks.iop.org/1464-4258/8/i=10/a=004 .
[CrossRef]

Harrison, P.

Z. Ikoni, R. W. Kelsall, and P. Harrison, “Waveguide design for mid- and far-infrared p-Si/SiGe quantum cascade lasers,” Semicond. Sci. Technol.19(1), 76–81 (2004), http://stacks.iop.org/0268-1242/19/i=1/a=013 .
[CrossRef]

Hochberg, M.

Hu, Y.

Ikoni, Z.

Z. Ikoni, R. W. Kelsall, and P. Harrison, “Waveguide design for mid- and far-infrared p-Si/SiGe quantum cascade lasers,” Semicond. Sci. Technol.19(1), 76–81 (2004), http://stacks.iop.org/0268-1242/19/i=1/a=013 .
[CrossRef]

Ilic, R.

Janz, S.

M. Robillard, P. E. Jessop, D. M. Bruce, S. Janz, R. L. Williams, S. Mailhot, H. Lafontaine, S. J. Kovacic, and J. J. Ojha, “Strain-induced birefringence in Si1-xGex optical waveguides,” J. Vac. Sci. Technol. B16(4), 1773–1776 (1998), http://link.aip.org/link/?JVB/16/1773/1 .
[CrossRef]

Jessop, P. E.

M. Robillard, P. E. Jessop, D. M. Bruce, S. Janz, R. L. Williams, S. Mailhot, H. Lafontaine, S. J. Kovacic, and J. J. Ojha, “Strain-induced birefringence in Si1-xGex optical waveguides,” J. Vac. Sci. Technol. B16(4), 1773–1776 (1998), http://link.aip.org/link/?JVB/16/1773/1 .
[CrossRef]

Kelsall, R. W.

Z. Ikoni, R. W. Kelsall, and P. Harrison, “Waveguide design for mid- and far-infrared p-Si/SiGe quantum cascade lasers,” Semicond. Sci. Technol.19(1), 76–81 (2004), http://stacks.iop.org/0268-1242/19/i=1/a=013 .
[CrossRef]

Kern, P.

Khomchenko, A. V.

A. V. Khomchenko, “M-lines technique application for studying of optical nonlinearities in thin films at a low light intensity,” Opt. Commun.201, 363–372 (2002), http://www.sciencedirect.com/science/article/pii/S0030401801016832 .

Kovacic, S. J.

M. Robillard, P. E. Jessop, D. M. Bruce, S. Janz, R. L. Williams, S. Mailhot, H. Lafontaine, S. J. Kovacic, and J. J. Ojha, “Strain-induced birefringence in Si1-xGex optical waveguides,” J. Vac. Sci. Technol. B16(4), 1773–1776 (1998), http://link.aip.org/link/?JVB/16/1773/1 .
[CrossRef]

Labadie, L.

Lafontaine, H.

M. Robillard, P. E. Jessop, D. M. Bruce, S. Janz, R. L. Williams, S. Mailhot, H. Lafontaine, S. J. Kovacic, and J. J. Ojha, “Strain-induced birefringence in Si1-xGex optical waveguides,” J. Vac. Sci. Technol. B16(4), 1773–1776 (1998), http://link.aip.org/link/?JVB/16/1773/1 .
[CrossRef]

Lorenzo, J. P.

Mailhot, S.

M. Robillard, P. E. Jessop, D. M. Bruce, S. Janz, R. L. Williams, S. Mailhot, H. Lafontaine, S. J. Kovacic, and J. J. Ojha, “Strain-induced birefringence in Si1-xGex optical waveguides,” J. Vac. Sci. Technol. B16(4), 1773–1776 (1998), http://link.aip.org/link/?JVB/16/1773/1 .
[CrossRef]

Martin, R. J.

P. K. Tien, R. Ulrich, and R. J. Martin, “Modes of propagating light waves in thin deposited semiconductor films,” Appl. Phys. Lett.14,291–294 (1969), http://link.aip.org/link/?APL/14/291/1 .

Mashanovich, G. Z.

Miloševic, M. M.

Namavar, F.

Nedeljkovic, M.

Ojha, J. J.

M. Robillard, P. E. Jessop, D. M. Bruce, S. Janz, R. L. Williams, S. Mailhot, H. Lafontaine, S. J. Kovacic, and J. J. Ojha, “Strain-induced birefringence in Si1-xGex optical waveguides,” J. Vac. Sci. Technol. B16(4), 1773–1776 (1998), http://link.aip.org/link/?JVB/16/1773/1 .
[CrossRef]

Owens, N.

Penkov, B.

Pogossian, S.

Pradel, A.

Robillard, M.

M. Robillard, P. E. Jessop, D. M. Bruce, S. Janz, R. L. Williams, S. Mailhot, H. Lafontaine, S. J. Kovacic, and J. J. Ojha, “Strain-induced birefringence in Si1-xGex optical waveguides,” J. Vac. Sci. Technol. B16(4), 1773–1776 (1998), http://link.aip.org/link/?JVB/16/1773/1 .
[CrossRef]

Soref, R.

R. Soref, S. Emelett, and W. Buchwald, “Silicon waveguided components for the long-wave infrared region,” J. Opt. A: Pure Appl. Opt8(10), 840–848 (2006), http://stacks.iop.org/1464-4258/8/i=10/a=004 .
[CrossRef]

Soref, R. A.

Spott, A.

Teo, E. J.

Tien, P. K.

P. K. Tien and R. Ulrich, “Theory of Prism-Film Coupler and Thin-Film Light Guides,” J. Opt. Soc. Am.60(10), 1325–1337 (1970).
[CrossRef]

P. K. Tien, R. Ulrich, and R. J. Martin, “Modes of propagating light waves in thin deposited semiconductor films,” Appl. Phys. Lett.14,291–294 (1969), http://link.aip.org/link/?APL/14/291/1 .

Ulrich, R.

P. K. Tien and R. Ulrich, “Theory of Prism-Film Coupler and Thin-Film Light Guides,” J. Opt. Soc. Am.60(10), 1325–1337 (1970).
[CrossRef]

P. K. Tien, R. Ulrich, and R. J. Martin, “Modes of propagating light waves in thin deposited semiconductor films,” Appl. Phys. Lett.14,291–294 (1969), http://link.aip.org/link/?APL/14/291/1 .

Vescan, L.

Vigreux-Bercovici, C.

Vonsovici, A.

Wallner, O.

Williams, R. L.

M. Robillard, P. E. Jessop, D. M. Bruce, S. Janz, R. L. Williams, S. Mailhot, H. Lafontaine, S. J. Kovacic, and J. J. Ojha, “Strain-induced birefringence in Si1-xGex optical waveguides,” J. Vac. Sci. Technol. B16(4), 1773–1776 (1998), http://link.aip.org/link/?JVB/16/1773/1 .
[CrossRef]

Xiong, B.

Appl. Phys. Lett.

P. K. Tien, R. Ulrich, and R. J. Martin, “Modes of propagating light waves in thin deposited semiconductor films,” Appl. Phys. Lett.14,291–294 (1969), http://link.aip.org/link/?APL/14/291/1 .

J. Opt. A: Pure Appl. Opt

R. Soref, S. Emelett, and W. Buchwald, “Silicon waveguided components for the long-wave infrared region,” J. Opt. A: Pure Appl. Opt8(10), 840–848 (2006), http://stacks.iop.org/1464-4258/8/i=10/a=004 .
[CrossRef]

J. Opt. Soc. Am.

J. Opt. Soc. Am. A

J. Vac. Sci. Technol. B

M. Robillard, P. E. Jessop, D. M. Bruce, S. Janz, R. L. Williams, S. Mailhot, H. Lafontaine, S. J. Kovacic, and J. J. Ojha, “Strain-induced birefringence in Si1-xGex optical waveguides,” J. Vac. Sci. Technol. B16(4), 1773–1776 (1998), http://link.aip.org/link/?JVB/16/1773/1 .
[CrossRef]

Opt. Commun.

A. V. Khomchenko, “M-lines technique application for studying of optical nonlinearities in thin films at a low light intensity,” Opt. Commun.201, 363–372 (2002), http://www.sciencedirect.com/science/article/pii/S0030401801016832 .

Opt. Express

Opt. Lett.

Semicond. Sci. Technol.

Z. Ikoni, R. W. Kelsall, and P. Harrison, “Waveguide design for mid- and far-infrared p-Si/SiGe quantum cascade lasers,” Semicond. Sci. Technol.19(1), 76–81 (2004), http://stacks.iop.org/0268-1242/19/i=1/a=013 .
[CrossRef]

Other

A. Trita, Integrated Optical Devices Based on Semiconductor Materials, (Phd dissertation, Universita Degli Studi Di Pavia 2008), Chap. 2.3, http://www-3.unipv.it/dottIEIE/tesi/2008/a_trita.pdf .

M. Brun, S. Nicoletti, and J. M. Hartmann, CEA-LETI, MINATEC Campus, 17 rue des Martyrs, 38054 Grenoble Cedex 9, FRANCE are preparing a manuscript to be called “Design, realization and characterization of SixGe1-x waveguides for MIR wavelengths”.

P. Yeh, Optical Waves in Layered Media (Wiley-interscience, 1988).

S. Valette, Etude et Réalisation de Guides d’Ondes Planaires dans le Tellurure de Zinc (Phd dissertation, Université scientifique et médicale de Grenoble, 1976).

A. W. Snyder and J. D. Love, Optical Waveguide Theory (Chapman and Hall, 1983).

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Figures (8)

Fig. 1
Fig. 1

(a) Schematic of the Si1-xGex stack. (b) Germanium concentration versus thickness, x = f(z), measured by SIMS. The sample consist of a Si1-xGex gradient layer deposited on a SOI substrate: Si / SiO2(2000nm) / Si(1200nm). The maximum Ge ratio is 0.38 and the total thickness of SiGe profile is 3100 nm.

Fig. 2
Fig. 2

(a) Experimental setup (Mlines) used to measure the coupling angles to the waveguide modes. The evanescent field generated by the laser beam (λ = 2.15µm) is coupled to the waveguide modes for specific angles. To ensure a good coupling, the substrate is mechanically pressed against the prism base. The InGaAs cooled detector placed on a rotation stage measures the angular reflectivity for both polarizations TE and TM. (b) Typical Mlines measurement of a constant composition Si1-xGex layer (x = 0.376 and thickness t = 2970 nm) deposited on a Si substrate. The three dips for each polarization correspond to the coupling angles to the waveguide modes.

Fig. 3
Fig. 3

Germanium content versus thickness, x = f(z), measured by SIMS for six samples. Each sample consists of a constant Ge composition Si1-xGex layer epitaxially grown on a Si(001) substrate.

Fig. 4
Fig. 4

(a) Cartography of the absolute difference (Δn = |neff_exp - neff_simu|) between experimental and simulated effective indexes for the three TE modes. X and Y coordinates correspond to the refractive index and thickness of the constant Ge composition waveguide. Each mode corresponds to a broad line plotted in false color. The broader line corresponds to TE0 mode, the middle one to TE1 and the thinner one to TE2. (b) Cartography of the mean value of |neff_exp - neff_simu| obtained for the six modes (3 TE + 3 TM) of the constant Ge composition SiGe layer.

Fig. 5
Fig. 5

Determination of the law n = f(x), experimental curve and best quadratic fit.

Fig. 6
Fig. 6

(a) Cartography of the absolute difference (Δn = |neff_exp - neff_simu|) between experimental and simulated effective indexes for the four TE modes. The sample consists of a Si1-xGex gradient layer deposited on a SOI substrate: Si / SiO2(2000nm) / Si(1200nm). xmax and tmax are homothetic coefficients applied to, respectively, the concentration and the thickness coordinates of the nominal SIMS plot presented in Fig. 1. Each mode corresponds to a broad line plotted in false colors. For a better readability, the plot is limited to Δn values smaller than 0.0015. This corresponds to 3σexp where σexp is the Mlines measurement accuracy. (b) Cartography of the average value of |neff_exp - neff_simu| obtained for eight modes (4 TE + 4 TM) of the gradient waveguide.

Fig. 7
Fig. 7

Cartography of the average value of |neff_exp - neff_simu| obtained for eight modes (4 TE + 4 TM) of trial sample #1.

Fig. 8
Fig. 8

Germanium depth profiles, x = f(z), obtained for four samples at various stages of a process optimization cycle, the target of which is the nominal profile (black curves). The blue curves are homothetic profiles of the black curves (the homothetic coefficients correspond to the best fit obtained from the Mlines measurement). The red curves are the real SIMS profiles.

Tables (1)

Tables Icon

Table 1 Ge contents, thicknesses and refractive indexes measured by SIMS and Mlines for the nine constant-composition Si1-xGex layers.

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