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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 17, Iss. 23 — Nov. 9, 2009
  • pp: 20891–20899
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Propagation losses in undoped and n-doped polycrystalline silicon wire waveguides

Shiyang Zhu, Q. Fang, M. B. Yu, G. Q. Lo, and D. L. Kwong  »View Author Affiliations


Optics Express, Vol. 17, Issue 23, pp. 20891-20899 (2009)
http://dx.doi.org/10.1364/OE.17.020891


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Abstract

Polycrystalline silicon (polySi) wire waveguides with width ranging from 200 to 500 nm are fabricated by solid-phase crystallization (SPC) of deposited amorphous silicon (a-Si) on SiO2 at a maximum temperature of 1000°C. The propagation loss at 1550 nm decreases from 13.0 to 9.8 dB/cm with the waveguide width shrinking from 500 to 300 nm while the 200-nm-wide waveguides exhibit quite large loss (>70 dB/cm) mainly due to the relatively rough sidewall of waveguides induced by the polySi dry etch. By modifying the process sequence, i.e., first patterning the a-Si layer into waveguides by dry etch and then SPC, the sidewall roughness is significantly improved but the polySi crystallinity is degraded, leading to 13.9 dB/cm loss in the 200-nm-wide waveguides while larger losses in the wider waveguides. Phosphorus implantation causes an additional loss in the polySi waveguides. The doping-induced optical loss increases relatively slowly with the phosphorus concentration increasing up to 1 × 1018 cm−3, whereas the 5 × 1018 cm−3 doped waveguides exhibit large loss due to the dominant free carrier absorption. For all undoped polySi waveguides, further 1–2 dB/cm loss reduction is obtained by a standard forming gas (10%H2 + 90%N2) annealing owing to the hydrogen passivation of Si dangling bonds present in polySi waveguides, achieving the lowest loss of 7.9 dB/cm in the 300-nm-wide polySi waveguides. However, for the phosphorus doped polySi waveguides, the propagation loss is slightly increased by the forming gas annealing.

© 2009 OSA

1. Introduction

Although most of the major advances in silicon photonics have been based on single-crystalline silicon-on-insulator (SOI), the demands for polycrystalline silicon (polySi) based photonic devices are increasing owing to the unique feature of polySi as it can be easily grown on almost any substrate by standard techniques and simultaneously it has electron mobility of the order of 100 cm2/V·s, making it still capable of being used as electrically active layers. In high-speed metal-oxide-semiconductor (MOS) capacitor-based silicon optical modulators and in horizontal slot waveguides for electrical injection [1

1. A. Liu, R. Jones, L. Liao, D. Samara-Rubio, D. Rubin, O. Cohen, R. Nicolaescu, and M. Paniccia, “A high-speed silicon optical modulator based on a metal-oxide-semiconductor capacitor,” Nature 427(6975), 615–618 ( 2004). [CrossRef] [PubMed]

,2

2. K. Preston and M. Lipson, “Slot waveguides with polycrystalline silicon for electrical injection,” Opt. Express 17(3), 1527–1534 ( 2009). [CrossRef] [PubMed]

], polySi has been utilized as part of the waveguide material above a thin oxide layer where the fabrication of a single-crystalline silicon layer is difficult. More importantly, polySi-based photonics provides a simple solution for multi-level or three-dimensional (3-D) integration of optical networks in Si integrated circuits. Ring resonators and electro-optics modulators entirely based on the deposited polySi films have been demonstrated recently [3

3. K. Preston, B. Schmidt, and M. Lipson, “Polysilicon photonic resonators for large-scale 3D integration of optical networks,” Opt. Express 15(25), 17283–17290 ( 2007). [CrossRef] [PubMed]

,4

4. K. Preston, S. Manipatruni, A. Gondarenko, C. B. Poitras, and M. Lipson, “Deposited silicon high-speed integrated electro-optic modulator,” Opt. Express 17(7), 5118–5124 ( 2009). [CrossRef] [PubMed]

].

However, polySi-based photonic devices suffer a major limitation − a relatively large propagation loss in polySi waveguides due to light absorption and scattering at the grain boundaries is present in polySi. Because polySi’s nature depends strongly on the fabrication details [5

5. T. Kamins, Polycrystalline Silicon for Integrated Circuits and Displays, 2nd ed., (Kluwer, 1998).

], the losses in polySi waveguides also depend strongly on the detailed fabrication process. Historically, polySi waveguides fabricated on directly deposited polySi layers exhibit very large optical loss (>70 dB/cm) mainly because of the rough surface of the polySi layer and/or the small grain size [6

6. A. Säynatjoki, J. Riikonen, H. Lipsanen, and J. Ahopelto, “Optical waveguides on polysilicon-on-insulator,” J. Mater. Sci. Mater. Electron. 14(5/7), 417–420 ( 2003). [CrossRef]

,7

7. J. S. Foresi, M. R. Black, A. M. Agarwal, and L. C. Kimerling, “Losses in polycrystalline silicon waveguides,” Appl. Phys. Lett. 68(15), 2052–2054 ( 1996). [CrossRef]

]. The loss was reduced to ~34 dB/cm after smoothing the surface by chemical mechanical polishing (CMP) [7

7. J. S. Foresi, M. R. Black, A. M. Agarwal, and L. C. Kimerling, “Losses in polycrystalline silicon waveguides,” Appl. Phys. Lett. 68(15), 2052–2054 ( 1996). [CrossRef]

]. On the other hand, polySi waveguides fabricated by solid-phase crystallization (SRC) of deposited amorphous silicon (a-Si) exhibit a relatively low loss due to its smooth surface and/or large grain size [8

8. L. Liao, D. R. Lim, A. M. Agarwal, X. Duan, K. K. Lee, and L. C. Kimerling, “Optical transmission losses in polycrystalline silicon strip waveguides: effects of waveguide dimensions, thermal treatment, hydrogen passivation, and wavelength,” J. Electron. Mater. 29(12), 1380–1386 ( 2000). [CrossRef]

,9

9. Q. Fang, J. F. Song, S. H. Tao, M. B. Yu, G. Q. Lo, and D. L. Kwong, “Low loss (approximately 6.45dB/cm) sub-micron polycrystalline silicon waveguide integrated with efficient SiON waveguide coupler,” Opt. Express 16(9), 6425–6432 ( 2008). [CrossRef] [PubMed]

]. ~11 dB/cm loss was reported for the 200-nm-thick polySi waveguides and the loss was further reduced to ~9 dB/cm by remote electron cyclotron resonance (R-ECR) plasma hydrogenation [8

8. L. Liao, D. R. Lim, A. M. Agarwal, X. Duan, K. K. Lee, and L. C. Kimerling, “Optical transmission losses in polycrystalline silicon strip waveguides: effects of waveguide dimensions, thermal treatment, hydrogen passivation, and wavelength,” J. Electron. Mater. 29(12), 1380–1386 ( 2000). [CrossRef]

]. By replacing the cladding material from SiO2 to SiON, ~6.45 dB/cm loss for the TE mode and ~7.11 dB/cm for the TM mode were reported [9

9. Q. Fang, J. F. Song, S. H. Tao, M. B. Yu, G. Q. Lo, and D. L. Kwong, “Low loss (approximately 6.45dB/cm) sub-micron polycrystalline silicon waveguide integrated with efficient SiON waveguide coupler,” Opt. Express 16(9), 6425–6432 ( 2008). [CrossRef] [PubMed]

], which approaches its SOI counterparts [10

10. Y. A. Vlasov and S. J. McNab, “Losses in single-mode silicon-on-insulator strip waveguides and bends,” Opt. Express 12(8), 1622–1631 ( 2004). [CrossRef] [PubMed]

]. However, in all the above reports [2

2. K. Preston and M. Lipson, “Slot waveguides with polycrystalline silicon for electrical injection,” Opt. Express 17(3), 1527–1534 ( 2009). [CrossRef] [PubMed]

4

4. K. Preston, S. Manipatruni, A. Gondarenko, C. B. Poitras, and M. Lipson, “Deposited silicon high-speed integrated electro-optic modulator,” Opt. Express 17(7), 5118–5124 ( 2009). [CrossRef] [PubMed]

,8

8. L. Liao, D. R. Lim, A. M. Agarwal, X. Duan, K. K. Lee, and L. C. Kimerling, “Optical transmission losses in polycrystalline silicon strip waveguides: effects of waveguide dimensions, thermal treatment, hydrogen passivation, and wavelength,” J. Electron. Mater. 29(12), 1380–1386 ( 2000). [CrossRef]

,9

9. Q. Fang, J. F. Song, S. H. Tao, M. B. Yu, G. Q. Lo, and D. L. Kwong, “Low loss (approximately 6.45dB/cm) sub-micron polycrystalline silicon waveguide integrated with efficient SiON waveguide coupler,” Opt. Express 16(9), 6425–6432 ( 2008). [CrossRef] [PubMed]

], a 1100°C/long-time annealing procedure was carried out in order to crystallize the a-Si into polySi with the maximum grain size. However, such a high thermal budget restricts the polySi layers to be fabricated before any doping procedure, thus making it difficult to be implemented in the 3-D integration and even in the MOS-type modulator fabrication because some doping procedures have to be done before the polySi waveguide fabrication. Thus, it is extremely important to reduce the thermal budget for the polySi waveguide fabrication without sacrificing its optical loss property. Moreover, when polySi is used as active layers in photonic devices, it is usually is doped. However, the doping effect on the optical loss in polySi waveguides has not been reported yet in literature.

In this work, firstly, the maximum temperature for the polySi waveguide fabrication is reduced from 1100°C to 1000°C. Secondly, two fabrication approaches are compared: in one (normal) approach, the as-deposited a-Si film is first crystallized into polySi and then this polySi film is patterned into waveguide structures by dry etch; in the other (modified) approach, the as-deposited a-Si film is first patterned into the waveguide structures by dry etch and then crystallized them into polySi. Thirdly, some polySi waveguides are uniformly doped by phosphorus with the concentration ranging from 1 × 1017 to 5 × 1018 cm−3 by ion implantation, and the doping effect on the propagation loss is evaluated. Finally, a standard forming gas (FG) annealing is carried out for some wafers and the influence of FG annealing on both undoped and n-doped polySi waveguides is investigated.

2. Experimental

In the modified approach, the a-Si film was first patterned with the waveguide structures using lithography and dry etched down to the SiO2 layer using a 50-nm-thick SiO2 layer as the hard mask. The same abovementioned dry etch recipe was used. Then, the a-Si wire waveguides were crystallized into polySi using the abovementioned two-step annealing procedure. The other processes are exactly the same as those in the normal approach. For comparison, some chips taken from the fabricated wafers were additionally annealed at 1100°C for 1 h in N2 ambient.

3. Results and discussion

3.1 Effect of waveguide width

Table 1

Table 1. Propagation losses at 1550 nm in various undoped polySi wire waveguides, extracted from the cutback method. The error is estimated to be less than ± 1.0 dB/cm.

table-icon
View This Table
summarizes the propagation losses at 1550 nm in the undoped polySi wire waveguides with height of 220 nm and widths of 200, 300, 400, and 500 nm, fabricated using the normal and the modified approaches. For waveguides fabricated by the normal approach (i.e., first SPC and then patterning), the propagation losses are 13.0, 11.3, and 9.8 dB/cm for width = 500, 400, and 300 nm, respectively, while the 200-nm-wide waveguides have large loss (>70 dB/cm). It is well known that the light attenuation in polySi waveguides can be attributed to two main origins: one relates to the light absorption and scattering at the grain boundaries present in the waveguides (namely the bulk loss) and the other relates to the light scattering at the core/cladding interface (namely the interface loss). Because the narrower wire waveguides contain relatively less grains in the waveguides and they confine light less tightly (i.e., the light mode spreads more widely in the surrounding SiO2 layer), the bulk loss decreases while the interface loss increases with the waveguide width shrinking. The results show that the overall loss decreases with the waveguide width shrinking from 500 to 300 nm, indicating that the bulk loss dominates in waveguides with the width larger than 300 nm. Because the bulk loss is determined by the grain size and/or crystalline fraction of polySi, which can be improved by higher temperature annealing, we can expect that polySi waveguides fabricated at lower temperature have larger bulk loss. This is seen in the 575°C annealed polySi waveguides which have much larger losses and this loss increases more rapidly with the waveguide width increasing from 300 to 500 nm (see Table 1). For the 1100°C annealed polySi waveguides reported in [9

9. Q. Fang, J. F. Song, S. H. Tao, M. B. Yu, G. Q. Lo, and D. L. Kwong, “Low loss (approximately 6.45dB/cm) sub-micron polycrystalline silicon waveguide integrated with efficient SiON waveguide coupler,” Opt. Express 16(9), 6425–6432 ( 2008). [CrossRef] [PubMed]

], on the other hand, the overall loss is relatively small and it decreases (not increases) slightly with the waveguide width increasing from 300 to 700 nm [9

9. Q. Fang, J. F. Song, S. H. Tao, M. B. Yu, G. Q. Lo, and D. L. Kwong, “Low loss (approximately 6.45dB/cm) sub-micron polycrystalline silicon waveguide integrated with efficient SiON waveguide coupler,” Opt. Express 16(9), 6425–6432 ( 2008). [CrossRef] [PubMed]

], indicating that the bulk loss is not the dominant contributor for those waveguides.

After an additional 1100°C/1 h annealing, the losses in the initial 1000°C annealed waveguides become 10.9, 10.0, and 11.1 dB/cm for widths of 300, 400, and 500 nm, respectively, very close to those reported by Liao et al. where the polySi layers were crystallized at a maximum temperature of 1100°C. We can see that the losses in the 400- and 500-nm-wide waveguides reduce slightly after the additional annealing, which can be attributed to the reduction of bulk loss due to the further crystallization of polySi. For the initial 575°C annealed polySi waveguides, as expected, the loss reduction is more significant after the additional 1100°C annealing. The 400- and 500-nm-wide waveguides have losses of 10.2 and 11.7 dB/cm, respectively, very close to those of the initial 1000°C annealed waveguides, indicating that the crystallization of polySi is almost saturated after the 1100°C annealing [9

9. Q. Fang, J. F. Song, S. H. Tao, M. B. Yu, G. Q. Lo, and D. L. Kwong, “Low loss (approximately 6.45dB/cm) sub-micron polycrystalline silicon waveguide integrated with efficient SiON waveguide coupler,” Opt. Express 16(9), 6425–6432 ( 2008). [CrossRef] [PubMed]

]. However, the loss in the 300-nm-wide waveguides becomes slightly larger after the additional 1100°C annealing, which should be attributed to the increase of interface loss because the higher temperature annealing may slightly roughen the polySi waveguide interface. The above results indicate that although the higher temperature annealing (here 1100°C) is beneficial for the bulk loss reduction due to the improvement in crystallinity, its contribution to the overall loss decreases with the waveguide width shrinking and it may even becomes detrimental to the overall loss as the interface loss may increase slightly after the higher temperature annealing. For the 300-nm waveguides, the 1000°C anneal is sufficient to reach the lowest overall loss.

3.2 Effect of fabrication approach

The losses of polySi waveguides fabricated by the modified approach are also listed in Table 1. The losses are 13.9, 16.3, 18.1, and 25.7 dB/cm for the waveguides with widths of 200, 300, 400, and 500 nm, respectively. We see that the 200-nm-wide waveguides have much lower loss than those fabricated by the normal approach, confirming that these waveguides really have a reasonable smooth sidewall. However, the wider waveguides have larger loss and the loss increases with the waveguide width more rapidly than those fabricated by the normal approach. It indicates that the waveguides fabricated by the modified approach have larger dominant bulk loss, most probably due to their smaller grain size and/or poorer crystallinity than those fabricated by the normal approach. Since the same thermal treatment is carried out in both approaches, it indicates that the crystallization of a-Si may be layout-dependent, namely, the crystallization of a-Si wire is not as effective as the crystallization of a-Si film under the same annealing condition. One possible reason may be attributed to the fact that the a-Si wire has a much larger interface-volume ratio than the a-Si film − since the initial nucleation may occur more easily at the interface and the subsequent grain growth may terminate at the interface, the grain size in the final polySi wire is smaller (thus containing more grain boundaries) than that in the final polySi film after the same thermal treatment. Another possible reason is that the grain growth rate in the a-Si wire may be smaller than that in the a-Si film under the same thermal treatment, thus leading to a smaller crystalline faction in the final polySi wire waveguides. To understand this behavior unambiguously, more experimental studies are necessary, such as refractive index measurement, x-ray diffraction (XRD), and transmission electron microscopy (TEM), etc. which is still ongoing. After an additional annealing at 1100°C for 1 h, as expected, the losses in waveguides with the width ≥ 300 nm are reduced due to further crystallization of the polySi waveguides, like those fabricated by the normal approach. However, the final losses in these waveguides (except the 200-nm-wide waveguides) after the additional 1100°C/1 h annealing are not as low as those fabricated by the normal approach, which can also be ascribed to the insufficient crystallization of polySi wire waveguides. For the 200-nm-wide waveguides, the loss keeps almost the same after the additional 1100°C annealing probably due to the contrary effects of the additional high-temperature annealing on the bulk loss and the interface loss.

Nevertheless, the modified approach can significantly improve the sidewall roughness of the polySi waveguides, which compensates the degradation of its crystallization. This approach can be used to fabricate very narrow wire waveguides (e.g., ≤200 nm) where the interface loss dominates. Furthermore, if the crystallization of a-Si wire can be improved, such as using the laser annealing technology, very low loss polySi wire waveguides may be expected.

3.3 Effect of phosphorus doping

3.4 Effect of forming gas anneal

It has been known that hydrogen passivation of dangling bonds at the grain boundaries in polySi waveguides can reduce the propagation loss [8

8. L. Liao, D. R. Lim, A. M. Agarwal, X. Duan, K. K. Lee, and L. C. Kimerling, “Optical transmission losses in polycrystalline silicon strip waveguides: effects of waveguide dimensions, thermal treatment, hydrogen passivation, and wavelength,” J. Electron. Mater. 29(12), 1380–1386 ( 2000). [CrossRef]

]. It was argued that among various passivation techniques, the standard forming gas (FG) annealing is not an effective technique to passivate the dangling bonds in polySi films [5

5. T. Kamins, Polycrystalline Silicon for Integrated Circuits and Displays, 2nd ed., (Kluwer, 1998).

]. However, there was a report that the polySi waveguide loss is reduced from ~14 to ~11 dB/cm after the FG annealing [12

12. A. Saynatjoki, S. Arpiainen, J. Ahopelto, and H. Lipsanen, “High-index-contrast optical waveguides on silicon”, AIP Conf. Proc. 772, 27th Intern. Conf. on the Physics of Semiconductors, 1537–1538 (2005).

].

Figure 3
Fig. 3 The forming gas anneal-induced loss variation ( = loss of FG annealed waveguide – loss of corresponding waveguide without the FG anneal) for undoped and doped polySi waveguides. The solid symbols represent those fabricated by the normal approach and the open symbols represent those fabricated by the modified approach.
shows the FG annealing induced loss variation of our undoped and n-doped polySi waveguides. For the undoped polySi waveguides fabricated by either the normal approach or the modified approach, ~1-2 dB/cm loss reduction is obtained after the standard FG annealing, in agreement to that reported in [11

11. F. P. Payne and J. P. R. Lacey, “A theoretical analysis of scattering loss from planar optical waveguides,” Opt. Quantum Electron. 26(10), 977–986 ( 1994). [CrossRef]

]. The lowest loss is achieved to be 7.9 dB/cm in the 300-nm-wide polySi waveguides and the 200-nm-wide polySi waveguides have a loss of 12.8 dB/cm. The effectiveness of the FG annealing for the loss reduction in undoped polySi waveguides may be attributed to the fact that the FG annealing is carried out after the waveguide patterning so that the surface-to-volume ratio is larger than that in the case of poly-Si film. The dangling bonds at the polySi waveguide sidewall can be passivated by hydrogen from the FG gas ambient, unlike in the case of polySi films where the passivation depends on the diffusion of hydrogen from the surface into the bulk. Several FG annealed chips were re-measured after storing them at room-temperature for several weeks, the measured propagation losses show no substantial variation, indicating that the FG annealing induced hydrogen in polySi waveguide is quite stable at room temperature.

However, for the phosphorus doped polySi waveguides, Fig. 3 shows that the loss increases, by ~0.1–4.9 dB/cm, after the FG annealing. The amount of loss increase depends on both the phosphorus concentration and the waveguide width: slightly larger for the higher phosphorus concentration. A possible explanation of this phenomenon is that the dangling bonds in the grain boundaries may already have combined with phosphorus because phosphorus in polySi tends to segregate at the grain boundaries [5

5. T. Kamins, Polycrystalline Silicon for Integrated Circuits and Displays, 2nd ed., (Kluwer, 1998).

], therefore, during the FG annealing, hydrogen cannot passivate the dangling bonds, instead, the hydrogen and phosphorus may form a cluster at the dangling sites during the FG annealing. These clusters may contribute to light absorption and/or scattering, leading to a slightly enhanced light attenuation in the FG annealed n-type doped polySi waveguides. More studies are still on-going to fully understand the physics beyond this phenomenon.

4. Conclusion

Acknowledgements

The authors would like to thank Ushida-san, Fujikata-san, and Nakamura-san from NEC, Japan, for useful discussions. The authors would also like to thank the staffs from the SPT Lab for their assistance in wafer fabrication, Ms. Sandy Wang from MMC Lab for wafer dicing, and Mr. Joseph Weisheng Ng from IME for English correction.

References and links

1.

A. Liu, R. Jones, L. Liao, D. Samara-Rubio, D. Rubin, O. Cohen, R. Nicolaescu, and M. Paniccia, “A high-speed silicon optical modulator based on a metal-oxide-semiconductor capacitor,” Nature 427(6975), 615–618 ( 2004). [CrossRef] [PubMed]

2.

K. Preston and M. Lipson, “Slot waveguides with polycrystalline silicon for electrical injection,” Opt. Express 17(3), 1527–1534 ( 2009). [CrossRef] [PubMed]

3.

K. Preston, B. Schmidt, and M. Lipson, “Polysilicon photonic resonators for large-scale 3D integration of optical networks,” Opt. Express 15(25), 17283–17290 ( 2007). [CrossRef] [PubMed]

4.

K. Preston, S. Manipatruni, A. Gondarenko, C. B. Poitras, and M. Lipson, “Deposited silicon high-speed integrated electro-optic modulator,” Opt. Express 17(7), 5118–5124 ( 2009). [CrossRef] [PubMed]

5.

T. Kamins, Polycrystalline Silicon for Integrated Circuits and Displays, 2nd ed., (Kluwer, 1998).

6.

A. Säynatjoki, J. Riikonen, H. Lipsanen, and J. Ahopelto, “Optical waveguides on polysilicon-on-insulator,” J. Mater. Sci. Mater. Electron. 14(5/7), 417–420 ( 2003). [CrossRef]

7.

J. S. Foresi, M. R. Black, A. M. Agarwal, and L. C. Kimerling, “Losses in polycrystalline silicon waveguides,” Appl. Phys. Lett. 68(15), 2052–2054 ( 1996). [CrossRef]

8.

L. Liao, D. R. Lim, A. M. Agarwal, X. Duan, K. K. Lee, and L. C. Kimerling, “Optical transmission losses in polycrystalline silicon strip waveguides: effects of waveguide dimensions, thermal treatment, hydrogen passivation, and wavelength,” J. Electron. Mater. 29(12), 1380–1386 ( 2000). [CrossRef]

9.

Q. Fang, J. F. Song, S. H. Tao, M. B. Yu, G. Q. Lo, and D. L. Kwong, “Low loss (approximately 6.45dB/cm) sub-micron polycrystalline silicon waveguide integrated with efficient SiON waveguide coupler,” Opt. Express 16(9), 6425–6432 ( 2008). [CrossRef] [PubMed]

10.

Y. A. Vlasov and S. J. McNab, “Losses in single-mode silicon-on-insulator strip waveguides and bends,” Opt. Express 12(8), 1622–1631 ( 2004). [CrossRef] [PubMed]

11.

F. P. Payne and J. P. R. Lacey, “A theoretical analysis of scattering loss from planar optical waveguides,” Opt. Quantum Electron. 26(10), 977–986 ( 1994). [CrossRef]

12.

A. Saynatjoki, S. Arpiainen, J. Ahopelto, and H. Lipsanen, “High-index-contrast optical waveguides on silicon”, AIP Conf. Proc. 772, 27th Intern. Conf. on the Physics of Semiconductors, 1537–1538 (2005).

13.

A. Harke, M. Krause, and J. Mueller, “Low-loss single mode amorphous silicon waveguides,” Electron. Lett. 41(25), 1377–1379 ( 2005). [CrossRef]

14.

R. A. Soref and B. R. Bennett, “Kramers-Kronig analysis of E-O switching in silicon,” SPIE Integr. Opt. Circuit Eng. 704, 32–37 ( 1986).

OCIS Codes
(130.3120) Integrated optics : Integrated optics devices
(230.3990) Optical devices : Micro-optical devices
(230.7370) Optical devices : Waveguides

ToC Category:
Integrated Optics

History
Original Manuscript: July 28, 2009
Revised Manuscript: September 8, 2009
Manuscript Accepted: September 9, 2009
Published: October 30, 2009

Citation
Shiyang Zhu, Q. Fang, M. B. Yu, G. Q. Lo, and D. L. Kwong, "Propagation losses in undoped and n-doped polycrystalline silicon wire waveguides," Opt. Express 17, 20891-20899 (2009)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-17-23-20891


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References

  1. A. Liu, R. Jones, L. Liao, D. Samara-Rubio, D. Rubin, O. Cohen, R. Nicolaescu, and M. Paniccia, “A high-speed silicon optical modulator based on a metal-oxide-semiconductor capacitor,” Nature 427(6975), 615–618 (2004). [CrossRef] [PubMed]
  2. K. Preston and M. Lipson, “Slot waveguides with polycrystalline silicon for electrical injection,” Opt. Express 17(3), 1527–1534 (2009). [CrossRef] [PubMed]
  3. K. Preston, B. Schmidt, and M. Lipson, “Polysilicon photonic resonators for large-scale 3D integration of optical networks,” Opt. Express 15(25), 17283–17290 (2007). [CrossRef] [PubMed]
  4. K. Preston, S. Manipatruni, A. Gondarenko, C. B. Poitras, and M. Lipson, “Deposited silicon high-speed integrated electro-optic modulator,” Opt. Express 17(7), 5118–5124 (2009). [CrossRef] [PubMed]
  5. T. Kamins, Polycrystalline Silicon for Integrated Circuits and Displays, 2nd ed., (Kluwer, 1998).
  6. A. Säynatjoki, J. Riikonen, H. Lipsanen, and J. Ahopelto, “Optical waveguides on polysilicon-on-insulator,” J. Mater. Sci. Mater. Electron. 14(5/7), 417–420 (2003). [CrossRef]
  7. J. S. Foresi, M. R. Black, A. M. Agarwal, and L. C. Kimerling, “Losses in polycrystalline silicon waveguides,” Appl. Phys. Lett. 68(15), 2052–2054 (1996). [CrossRef]
  8. L. Liao, D. R. Lim, A. M. Agarwal, X. Duan, K. K. Lee, and L. C. Kimerling, “Optical transmission losses in polycrystalline silicon strip waveguides: effects of waveguide dimensions, thermal treatment, hydrogen passivation, and wavelength,” J. Electron. Mater. 29(12), 1380–1386 (2000). [CrossRef]
  9. Q. Fang, J. F. Song, S. H. Tao, M. B. Yu, G. Q. Lo, and D. L. Kwong, “Low loss (approximately 6.45dB/cm) sub-micron polycrystalline silicon waveguide integrated with efficient SiON waveguide coupler,” Opt. Express 16(9), 6425–6432 (2008). [CrossRef] [PubMed]
  10. Y. A. Vlasov and S. J. McNab, “Losses in single-mode silicon-on-insulator strip waveguides and bends,” Opt. Express 12(8), 1622–1631 (2004). [CrossRef] [PubMed]
  11. F. P. Payne and J. P. R. Lacey, “A theoretical analysis of scattering loss from planar optical waveguides,” Opt. Quantum Electron. 26(10), 977–986 (1994). [CrossRef]
  12. A. Saynatjoki, S. Arpiainen, J. Ahopelto, and H. Lipsanen, “High-index-contrast optical waveguides on silicon”, AIP Conf. Proc. 772, 27th Intern. Conf. on the Physics of Semiconductors, 1537–1538 (2005).
  13. A. Harke, M. Krause, and J. Mueller, “Low-loss single mode amorphous silicon waveguides,” Electron. Lett. 41(25), 1377–1379 (2005). [CrossRef]
  14. R. A. Soref and B. R. Bennett, “Kramers-Kronig analysis of E-O switching in silicon,” SPIE Integr. Opt. Circuit Eng. 704, 32–37 (1986).

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