Abstract

We have proposed a new approach to tune the operation wavelength of Franz-Keldysh Ge electro-absorption modulation in Si photonics by controlling the local strain environment to cover the whole range of C + L bands (1.53 – 1.62 μm). The present paper shows a proof of strain-tuning modulator concept by the shift of the Ge absorption edge using SiNx stressor films and Franz-Keldysh effect in strain-controlled Ge.

©2013 Optical Society of America

1. Introduction

Si photonics is an enabler of high-speed data communications as well as high performance computing. Optical modulators are currently one of the most critical devices and have achieved significant progress. However, there are still significant issues yet to be solved such as miniaturization of Mach-Zehnder modulator for high energy efficiency, temperature thermal stabilization of microring modulator reducing energy efficiency. On the other hand, the Franz-Keldysh (FK) electro-absorption (EA) modulators have various advantages over these modulators, such as low energy per bit, thermal stability, etc. It has recently been reported that Ge has a FK coefficient as large as that of III-V compound semiconductors [1], and Ge EA modulators have been prototyped to verify such small and low power operation characteristics [2,3]. The challenge is, however, that its operation wavelength window is narrow (0.015 μm) which requires a couple of SiGe modulators with different alloy composition is needed to cover the whole C + L bands (1.53-1.62 μm) [2]. We have proposed a new approach to tune the Ge bandgap with strain to cover the whole C + L band [4]. Since elastic deformation changes semiconductor bandgap, strained Ge should be an excellent material of FK EA modulator for working at C band as well as L band. The benefit of the present concept is Ge epitaxially grown for photodetector should be used as modulator as well. Localized SiNx stressors on Ge photodetector for redshift in responsivity has been experimentally demonstrated [5]. This paper reproduces a redshift in absorption edge of Ge tensile-strained by silicon nitride film in term of k·p theory and deformation potentials, and the shift is induced by external reverse biasing and reproduced by the FK effect.

2. Theoretical background

We carry the following theoretical calculation to verify the concept. The effect of strain on bandgap can be simulated with k·p theory and deformation potentials [6,7]. The boundary conditions are following: A Ge(001) waveguide is infinitely long along [010] and is stressed along [100]. The strain along [010] should not be changed upon such stressing, and thus the strain distribution is easily obtained in two dimensions across the cross section of the Ge waveguide on Si with stressor films side-by-side. The strained Ge as noted above introduces non-degeneracy in the valence band by splitting light-holes (LH) and of heavy-holes (HH), resulting in two bandgaps, C-LH and C-HH, where C stands for electrons in the conduction band. In addition, Ge epilayers on Si are strained biaxial-tensile in as-grown state due to thermal mismatch in cooling [8]. The built-in strain was measured to be 0.17% in our epilayers. Figure 1 shows the absorption edge dependence on [100] uniaxial stress applied to Ge strained biaxially tensile. It predicts that the uniaxial stress application to Ge ranging from + 0.2 to −0.9 GPa should cover the whole C + L bands. However, when we also consider the transition between conduction band and heavy hole band, the stress requirement could be smaller, only from + 0.2 to −0.4 GPa.

 figure: Fig. 1

Fig. 1 The theoretical relationship of the absorption edge of Ge with applied stress along [010] on Ge(100).

Download Full Size | PPT Slide | PDF

3. Experimental procedures

We designed and fabricated free space pin Ge photodetectors with silicon nitride (SiNx) stressors to verify the prediction. 400 nm-thick Ge(001) epilayers were grown on p+ Si(001) substrates at 600þC and 50 nm-thick Si cap layers were on it using ultra-high vacuum chemical vapor epitaxy (UHV-CVD). 300 nm-thick SiO2 films were deposited on these epilayers by plasma sputtering as a mask of implantation and as an insulator between Ge and electrode pads. Then phosphorus ions were implanted as a peak concentration of 1019 cm−3 to make pin diodes with 500 μm wide square regions. Phosphorus ions were implanted twice at 10 and 30 keV to make a good electric contact of the Si cap and to avoid hole accumulation at the interface between the Si-cap and Ge. The latter precisely applied the electric field by external biasing [9]. The samples were annealed at 600þC for 30 min. 500 nm-thick SiNx film was finally deposited using an Electron-Cyclotron Resonance plasma-enhanced Chemical Vapor Deposition (ECR-PECVD) method with SiH4 and N2 gases, and was then patterned into 500 μm long stripes of 500 nm width with intervals of 500 nm. This film has built-in stress of −760 MPa measured from the wafer warpage. Al was deposited for an electrical contact layer and then removed on SiNx, allowing free space light illuminated only on Ge under the SiNx stripes. The cross section of the Ge diodes is schematically shown in Fig. 2(a).

 figure: Fig. 2

Fig. 2 (a) The schematics of cross-section of the strained Ge photodetector and the reference photodetector. (b) The stress profile of the strained Ge photodetector.

Download Full Size | PPT Slide | PDF

4. Strain induced absorption edge shift

The stress distributions in the Ge diodes were measured by scanning μ-Raman spectroscopy. We performed mapping measurement in the perpendicular direction to the SiNx stripe with 0.5 μm intervals. 457 nm laser was used with the penetration depth in Ge of 18.7 nm. Although Ge layer is 400 nm thick, we demonstrated that the depth profile is constant [4]. Tensile stress is generated under the SiNx stripes, and compressive stress between stripes as in Fig. 2(b) [10]. Typically, SiNx with tensile built-in stress would apply a uniaxial compressive strain to the underlying Ge [11]. It should be marked here that our SiNx film has compressive built-in stress; therefore, the Ge layer under the SiNx stripes was strained tensile. We have found 200 MPa of tensile stress under SiNx stressors, which predicts about 0.02 μm redshift in the Ge absorption edge, corresponding to the L band edge 1.62 μm as in Fig. 1.

The responsivity spectra of the Ge photodetectors were measured with and without the SiNx stressor stripes in the wavelength range from 1400 to 1700 nm with the constant laser power of 0.815 mW to prevent band flattening. Figure 3 shows typical responsivity spectra of the Ge photodetectors with and without the stressors. The experimental redshift of Ge photodetector with the SiNx stressor reproduces the theory prediction.

 figure: Fig. 3

Fig. 3 The responsitivity spectra of free space Ge photodetectors with and without stressors.

Download Full Size | PPT Slide | PDF

5. Franz-Keldysh absorption change in strained Ge

Figure 4 shows the responsivity spectra of the Ge photodetector with the SiNx stressors under different applied reverse bias and indicates the occurrence of an electro-absorption effect.

 figure: Fig. 4

Fig. 4 The responsivity spectra of free space Ge photodetectors with SiNx stressors.

Download Full Size | PPT Slide | PDF

To analyze these data with the generalized Franz-Keldysh formalism [12], we have simulated the strength of the electric field from the profile by implanted P and p + Si using the one-dimensional finite-difference simulator (PC1D). The depth profile of the electric field strength is shown in Fig. 5(a). Since we implanted phosphorus at the Si cap and Ge interface, no electric field changes in the heavily P implanted region upon external biasing. Thus, no change in absorption should occur in the heavily P doped region by external biasing. In other words, the external bias only changes the electric field in the i-region located deeper from the diode surface. Taking the effect into account, we should modify the equation to express figure of merit (FOM), i.e., Δα/α, where Δα is the difference between the absorption coefficients with and without reverse bias and α is the absorption coefficient without reverse bias. FOM should be expressed as:

Δαα(exp)=(α(V)α(0))α(0)×tit,
Δαα(real)=Δαα(exp)×tti,
where ti is the thickness of the i-region and t is the thickness of the whole Ge layer. Δα/α(exp) is the FOM calculated directly from photocurrent spectra and Δα/α(real) is the one after calibration by Eq. (2). One should notice here is that in the electric filed profile, we still have some electric field slope in the region between the heavily doped region and i-region. For further improving precision of our simulation, we have divided it into many step regions shown in Fig. 5(a), and calculated the change of the absorption coefficient for each step. Then, we have plotted Δα/α(real) as a function of the applied reverse bias as w/ steps in Fig. 5(b). Here, we have considered a built-in electric field of the detector when no bias is applied. As in Fig. 5(b), while the theory without the consideration of many step regions and the experiment data are not it good agreement at high bias, theory reproduces the experimental data very well with the consideration of the electric field slope, confirming that the Franz-Keldysh effect dominates the electro-absorption of the intentionally strained Ge photodetectors.

 figure: Fig. 5

Fig. 5 (a) The electric field profile of the Ge photodetector with stressors. The depth profile is calculated using P and B profiles of the Ge epilayer. (b) Figure of merit Δα/α at wavelength of 1640 nm as a function of applied reverse bias.

Download Full Size | PPT Slide | PDF

6. Conclusions

The strain-tuning concept has been proven to show a redshift in the Ge absorption edge and the Frank-Keldysh formalism reproduced the experimental result. The stress-tuning concept we proposed for Ge EA modulators to cover the whole C + L bands. It should be marked that the thickness and width of the SiNx stripes will change the amount of strain in Ge and can be controlled in the back end process line.

Acknowledgments

A part of this research is granted by JSPS through FIRST Program initiated by CSTP. The samples were fabricated using an EB writer F5112 + VD01 in VLSI Design and Education Center (VDEC), the University of Tokyo, donated by ADVANTEST Corporation with the collaboration with Cadence Corporation.

References and links

1. S. Jongthammanurak, J. Liu, K. Wada, D. D. Cannon, D. T. Danielson, D. Pan, L. C. Kimerling, and J. Michel, “Large electro-optic effect in tensile strained Ge-on-Si films,” Appl. Phys. Lett. 89(16), 161115 (2006). [CrossRef]  

2. J. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, “Waveguide- integrated ultralow-energy GeSi electro-absorption modulators,” Nat. Photonics 2(7), 433–437 (2008). [CrossRef]  

3. A. E. Lim, T. Y. Liow, F. Qing, N. Duan, L. Ding, M. Yu, G. Q. Lo, and D. L. Kwong, “Novel evanescent-coupled germanium electro-absorption modulator featuring monolithic integration with germanium p-i-n photodetector,” Opt. Express 19(6), 5040–5046 (2011). [CrossRef]   [PubMed]  

4. R. Kuroyanagi, Y. Ishikawa, T. Tsuchizawa, S. Itabashi, and K. Wada, “Controlling strain in Ge on Si for EA modulators,” Proc. IEEE GFP8, 211–213 (2011). [CrossRef]  

5. L. Ding, T. Liow, E. Lim, N. Duan, M. Yu, and G. Lo, “Ge waveguide photodetectors with responsivity roll-off beyond 1620 nm using localized stressor,” OFC/NFOEC Tech. Digest, OW3G.4, 1–3 (2012)

6. C. G. Van de Walle, “Band lineups and deformation potentials in the model-solid theory,” Phys. Rev. B Condens. Matter 39(3), 1871–1883 (1989). [CrossRef]   [PubMed]  

7. J. Liu, D. D. Cannon, K. Wada, Y. Ishikawa, D. T. Danielson, S. Jongthammanurak, J. Michel, and L. C. Kimerling, “Deformation potential constants of biaxially tensile strained Ge epitaxial films on Si(100),” Phys. Rev. B 70(15), 155309 (2004). [CrossRef]  

8. Y. Ishikawa, K. Wada, J. Liu, D. D. Cannon, H. Liao, J. Micheal, and L. C. Kimerling, “Strain-induced enhancement of near-infrared absorption in Ge epitaxial layers grown on Si substrate,” J. Appl. Phys. 98(1), 013501 (2005). [CrossRef]  

9. S. B. Park, S. Takita, Y. Ishikawa, J. Osaka, and K. Wada, “Reserve current reduction of Ge photodiodes on Si without post-growth annealing,” Chin. Opt. Lett. 7(4), 286–290 (2009). [CrossRef]  

10. A. Ogura, H. Saitoh, D. Kosemura, Y. Kakemura, T. Yoshida, M. Takei, T. Koganezawa, I. Hirosawa, M. Kohno, T. Nishita, and T. Nakanishi, “Evaluation and control of Strain in Si induced by patterned SiN stressor,” Electrochem. Solid-State Lett. 12(4), H117–H119 (2009). [CrossRef]  

11. L. Ding, A. E. Lim, J. T. Liow, M. B. Yu, and G. Q. Lo, “Dependences of photoluminescence from P-implanted epitaxial Ge,” Opt. Express 20(8), 8228–8239 (2012). [CrossRef]   [PubMed]  

12. H. Shen and F. H. Pollak, “Generalized Franz-Keldysh theory of electromodulation,” Phys. Rev. B Condens. Matter 42(11), 7097–7102 (1990). [CrossRef]   [PubMed]  

References

  • View by:
  • |
  • |
  • |

  1. S. Jongthammanurak, J. Liu, K. Wada, D. D. Cannon, D. T. Danielson, D. Pan, L. C. Kimerling, and J. Michel, “Large electro-optic effect in tensile strained Ge-on-Si films,” Appl. Phys. Lett. 89(16), 161115 (2006).
    [Crossref]
  2. J. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, “Waveguide- integrated ultralow-energy GeSi electro-absorption modulators,” Nat. Photonics 2(7), 433–437 (2008).
    [Crossref]
  3. A. E. Lim, T. Y. Liow, F. Qing, N. Duan, L. Ding, M. Yu, G. Q. Lo, and D. L. Kwong, “Novel evanescent-coupled germanium electro-absorption modulator featuring monolithic integration with germanium p-i-n photodetector,” Opt. Express 19(6), 5040–5046 (2011).
    [Crossref] [PubMed]
  4. R. Kuroyanagi, Y. Ishikawa, T. Tsuchizawa, S. Itabashi, and K. Wada, “Controlling strain in Ge on Si for EA modulators,” Proc. IEEE GFP8, 211–213 (2011).
    [Crossref]
  5. L. Ding, T. Liow, E. Lim, N. Duan, M. Yu, and G. Lo, “Ge waveguide photodetectors with responsivity roll-off beyond 1620 nm using localized stressor,” OFC/NFOEC Tech. Digest, OW3G.4, 1–3 (2012)
  6. C. G. Van de Walle, “Band lineups and deformation potentials in the model-solid theory,” Phys. Rev. B Condens. Matter 39(3), 1871–1883 (1989).
    [Crossref] [PubMed]
  7. J. Liu, D. D. Cannon, K. Wada, Y. Ishikawa, D. T. Danielson, S. Jongthammanurak, J. Michel, and L. C. Kimerling, “Deformation potential constants of biaxially tensile strained Ge epitaxial films on Si(100),” Phys. Rev. B 70(15), 155309 (2004).
    [Crossref]
  8. Y. Ishikawa, K. Wada, J. Liu, D. D. Cannon, H. Liao, J. Micheal, and L. C. Kimerling, “Strain-induced enhancement of near-infrared absorption in Ge epitaxial layers grown on Si substrate,” J. Appl. Phys. 98(1), 013501 (2005).
    [Crossref]
  9. S. B. Park, S. Takita, Y. Ishikawa, J. Osaka, and K. Wada, “Reserve current reduction of Ge photodiodes on Si without post-growth annealing,” Chin. Opt. Lett. 7(4), 286–290 (2009).
    [Crossref]
  10. A. Ogura, H. Saitoh, D. Kosemura, Y. Kakemura, T. Yoshida, M. Takei, T. Koganezawa, I. Hirosawa, M. Kohno, T. Nishita, and T. Nakanishi, “Evaluation and control of Strain in Si induced by patterned SiN stressor,” Electrochem. Solid-State Lett. 12(4), H117–H119 (2009).
    [Crossref]
  11. L. Ding, A. E. Lim, J. T. Liow, M. B. Yu, and G. Q. Lo, “Dependences of photoluminescence from P-implanted epitaxial Ge,” Opt. Express 20(8), 8228–8239 (2012).
    [Crossref] [PubMed]
  12. H. Shen and F. H. Pollak, “Generalized Franz-Keldysh theory of electromodulation,” Phys. Rev. B Condens. Matter 42(11), 7097–7102 (1990).
    [Crossref] [PubMed]

2012 (1)

2011 (1)

2009 (2)

S. B. Park, S. Takita, Y. Ishikawa, J. Osaka, and K. Wada, “Reserve current reduction of Ge photodiodes on Si without post-growth annealing,” Chin. Opt. Lett. 7(4), 286–290 (2009).
[Crossref]

A. Ogura, H. Saitoh, D. Kosemura, Y. Kakemura, T. Yoshida, M. Takei, T. Koganezawa, I. Hirosawa, M. Kohno, T. Nishita, and T. Nakanishi, “Evaluation and control of Strain in Si induced by patterned SiN stressor,” Electrochem. Solid-State Lett. 12(4), H117–H119 (2009).
[Crossref]

2008 (1)

J. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, “Waveguide- integrated ultralow-energy GeSi electro-absorption modulators,” Nat. Photonics 2(7), 433–437 (2008).
[Crossref]

2006 (1)

S. Jongthammanurak, J. Liu, K. Wada, D. D. Cannon, D. T. Danielson, D. Pan, L. C. Kimerling, and J. Michel, “Large electro-optic effect in tensile strained Ge-on-Si films,” Appl. Phys. Lett. 89(16), 161115 (2006).
[Crossref]

2005 (1)

Y. Ishikawa, K. Wada, J. Liu, D. D. Cannon, H. Liao, J. Micheal, and L. C. Kimerling, “Strain-induced enhancement of near-infrared absorption in Ge epitaxial layers grown on Si substrate,” J. Appl. Phys. 98(1), 013501 (2005).
[Crossref]

2004 (1)

J. Liu, D. D. Cannon, K. Wada, Y. Ishikawa, D. T. Danielson, S. Jongthammanurak, J. Michel, and L. C. Kimerling, “Deformation potential constants of biaxially tensile strained Ge epitaxial films on Si(100),” Phys. Rev. B 70(15), 155309 (2004).
[Crossref]

1990 (1)

H. Shen and F. H. Pollak, “Generalized Franz-Keldysh theory of electromodulation,” Phys. Rev. B Condens. Matter 42(11), 7097–7102 (1990).
[Crossref] [PubMed]

1989 (1)

C. G. Van de Walle, “Band lineups and deformation potentials in the model-solid theory,” Phys. Rev. B Condens. Matter 39(3), 1871–1883 (1989).
[Crossref] [PubMed]

Beals, M.

J. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, “Waveguide- integrated ultralow-energy GeSi electro-absorption modulators,” Nat. Photonics 2(7), 433–437 (2008).
[Crossref]

Bernardis, S.

J. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, “Waveguide- integrated ultralow-energy GeSi electro-absorption modulators,” Nat. Photonics 2(7), 433–437 (2008).
[Crossref]

Cannon, D. D.

S. Jongthammanurak, J. Liu, K. Wada, D. D. Cannon, D. T. Danielson, D. Pan, L. C. Kimerling, and J. Michel, “Large electro-optic effect in tensile strained Ge-on-Si films,” Appl. Phys. Lett. 89(16), 161115 (2006).
[Crossref]

Y. Ishikawa, K. Wada, J. Liu, D. D. Cannon, H. Liao, J. Micheal, and L. C. Kimerling, “Strain-induced enhancement of near-infrared absorption in Ge epitaxial layers grown on Si substrate,” J. Appl. Phys. 98(1), 013501 (2005).
[Crossref]

J. Liu, D. D. Cannon, K. Wada, Y. Ishikawa, D. T. Danielson, S. Jongthammanurak, J. Michel, and L. C. Kimerling, “Deformation potential constants of biaxially tensile strained Ge epitaxial films on Si(100),” Phys. Rev. B 70(15), 155309 (2004).
[Crossref]

Cheng, J.

J. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, “Waveguide- integrated ultralow-energy GeSi electro-absorption modulators,” Nat. Photonics 2(7), 433–437 (2008).
[Crossref]

Danielson, D. T.

S. Jongthammanurak, J. Liu, K. Wada, D. D. Cannon, D. T. Danielson, D. Pan, L. C. Kimerling, and J. Michel, “Large electro-optic effect in tensile strained Ge-on-Si films,” Appl. Phys. Lett. 89(16), 161115 (2006).
[Crossref]

J. Liu, D. D. Cannon, K. Wada, Y. Ishikawa, D. T. Danielson, S. Jongthammanurak, J. Michel, and L. C. Kimerling, “Deformation potential constants of biaxially tensile strained Ge epitaxial films on Si(100),” Phys. Rev. B 70(15), 155309 (2004).
[Crossref]

Ding, L.

Duan, N.

A. E. Lim, T. Y. Liow, F. Qing, N. Duan, L. Ding, M. Yu, G. Q. Lo, and D. L. Kwong, “Novel evanescent-coupled germanium electro-absorption modulator featuring monolithic integration with germanium p-i-n photodetector,” Opt. Express 19(6), 5040–5046 (2011).
[Crossref] [PubMed]

L. Ding, T. Liow, E. Lim, N. Duan, M. Yu, and G. Lo, “Ge waveguide photodetectors with responsivity roll-off beyond 1620 nm using localized stressor,” OFC/NFOEC Tech. Digest, OW3G.4, 1–3 (2012)

Hirosawa, I.

A. Ogura, H. Saitoh, D. Kosemura, Y. Kakemura, T. Yoshida, M. Takei, T. Koganezawa, I. Hirosawa, M. Kohno, T. Nishita, and T. Nakanishi, “Evaluation and control of Strain in Si induced by patterned SiN stressor,” Electrochem. Solid-State Lett. 12(4), H117–H119 (2009).
[Crossref]

Ishikawa, Y.

S. B. Park, S. Takita, Y. Ishikawa, J. Osaka, and K. Wada, “Reserve current reduction of Ge photodiodes on Si without post-growth annealing,” Chin. Opt. Lett. 7(4), 286–290 (2009).
[Crossref]

Y. Ishikawa, K. Wada, J. Liu, D. D. Cannon, H. Liao, J. Micheal, and L. C. Kimerling, “Strain-induced enhancement of near-infrared absorption in Ge epitaxial layers grown on Si substrate,” J. Appl. Phys. 98(1), 013501 (2005).
[Crossref]

J. Liu, D. D. Cannon, K. Wada, Y. Ishikawa, D. T. Danielson, S. Jongthammanurak, J. Michel, and L. C. Kimerling, “Deformation potential constants of biaxially tensile strained Ge epitaxial films on Si(100),” Phys. Rev. B 70(15), 155309 (2004).
[Crossref]

R. Kuroyanagi, Y. Ishikawa, T. Tsuchizawa, S. Itabashi, and K. Wada, “Controlling strain in Ge on Si for EA modulators,” Proc. IEEE GFP8, 211–213 (2011).
[Crossref]

Itabashi, S.

R. Kuroyanagi, Y. Ishikawa, T. Tsuchizawa, S. Itabashi, and K. Wada, “Controlling strain in Ge on Si for EA modulators,” Proc. IEEE GFP8, 211–213 (2011).
[Crossref]

Jongthammanurak, S.

S. Jongthammanurak, J. Liu, K. Wada, D. D. Cannon, D. T. Danielson, D. Pan, L. C. Kimerling, and J. Michel, “Large electro-optic effect in tensile strained Ge-on-Si films,” Appl. Phys. Lett. 89(16), 161115 (2006).
[Crossref]

J. Liu, D. D. Cannon, K. Wada, Y. Ishikawa, D. T. Danielson, S. Jongthammanurak, J. Michel, and L. C. Kimerling, “Deformation potential constants of biaxially tensile strained Ge epitaxial films on Si(100),” Phys. Rev. B 70(15), 155309 (2004).
[Crossref]

Kakemura, Y.

A. Ogura, H. Saitoh, D. Kosemura, Y. Kakemura, T. Yoshida, M. Takei, T. Koganezawa, I. Hirosawa, M. Kohno, T. Nishita, and T. Nakanishi, “Evaluation and control of Strain in Si induced by patterned SiN stressor,” Electrochem. Solid-State Lett. 12(4), H117–H119 (2009).
[Crossref]

Kimerling, L. C.

J. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, “Waveguide- integrated ultralow-energy GeSi electro-absorption modulators,” Nat. Photonics 2(7), 433–437 (2008).
[Crossref]

S. Jongthammanurak, J. Liu, K. Wada, D. D. Cannon, D. T. Danielson, D. Pan, L. C. Kimerling, and J. Michel, “Large electro-optic effect in tensile strained Ge-on-Si films,” Appl. Phys. Lett. 89(16), 161115 (2006).
[Crossref]

Y. Ishikawa, K. Wada, J. Liu, D. D. Cannon, H. Liao, J. Micheal, and L. C. Kimerling, “Strain-induced enhancement of near-infrared absorption in Ge epitaxial layers grown on Si substrate,” J. Appl. Phys. 98(1), 013501 (2005).
[Crossref]

J. Liu, D. D. Cannon, K. Wada, Y. Ishikawa, D. T. Danielson, S. Jongthammanurak, J. Michel, and L. C. Kimerling, “Deformation potential constants of biaxially tensile strained Ge epitaxial films on Si(100),” Phys. Rev. B 70(15), 155309 (2004).
[Crossref]

Koganezawa, T.

A. Ogura, H. Saitoh, D. Kosemura, Y. Kakemura, T. Yoshida, M. Takei, T. Koganezawa, I. Hirosawa, M. Kohno, T. Nishita, and T. Nakanishi, “Evaluation and control of Strain in Si induced by patterned SiN stressor,” Electrochem. Solid-State Lett. 12(4), H117–H119 (2009).
[Crossref]

Kohno, M.

A. Ogura, H. Saitoh, D. Kosemura, Y. Kakemura, T. Yoshida, M. Takei, T. Koganezawa, I. Hirosawa, M. Kohno, T. Nishita, and T. Nakanishi, “Evaluation and control of Strain in Si induced by patterned SiN stressor,” Electrochem. Solid-State Lett. 12(4), H117–H119 (2009).
[Crossref]

Kosemura, D.

A. Ogura, H. Saitoh, D. Kosemura, Y. Kakemura, T. Yoshida, M. Takei, T. Koganezawa, I. Hirosawa, M. Kohno, T. Nishita, and T. Nakanishi, “Evaluation and control of Strain in Si induced by patterned SiN stressor,” Electrochem. Solid-State Lett. 12(4), H117–H119 (2009).
[Crossref]

Kuroyanagi, R.

R. Kuroyanagi, Y. Ishikawa, T. Tsuchizawa, S. Itabashi, and K. Wada, “Controlling strain in Ge on Si for EA modulators,” Proc. IEEE GFP8, 211–213 (2011).
[Crossref]

Kwong, D. L.

Liao, H.

Y. Ishikawa, K. Wada, J. Liu, D. D. Cannon, H. Liao, J. Micheal, and L. C. Kimerling, “Strain-induced enhancement of near-infrared absorption in Ge epitaxial layers grown on Si substrate,” J. Appl. Phys. 98(1), 013501 (2005).
[Crossref]

Lim, A. E.

Lim, E.

L. Ding, T. Liow, E. Lim, N. Duan, M. Yu, and G. Lo, “Ge waveguide photodetectors with responsivity roll-off beyond 1620 nm using localized stressor,” OFC/NFOEC Tech. Digest, OW3G.4, 1–3 (2012)

Liow, J. T.

Liow, T.

L. Ding, T. Liow, E. Lim, N. Duan, M. Yu, and G. Lo, “Ge waveguide photodetectors with responsivity roll-off beyond 1620 nm using localized stressor,” OFC/NFOEC Tech. Digest, OW3G.4, 1–3 (2012)

Liow, T. Y.

Liu, J.

J. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, “Waveguide- integrated ultralow-energy GeSi electro-absorption modulators,” Nat. Photonics 2(7), 433–437 (2008).
[Crossref]

S. Jongthammanurak, J. Liu, K. Wada, D. D. Cannon, D. T. Danielson, D. Pan, L. C. Kimerling, and J. Michel, “Large electro-optic effect in tensile strained Ge-on-Si films,” Appl. Phys. Lett. 89(16), 161115 (2006).
[Crossref]

Y. Ishikawa, K. Wada, J. Liu, D. D. Cannon, H. Liao, J. Micheal, and L. C. Kimerling, “Strain-induced enhancement of near-infrared absorption in Ge epitaxial layers grown on Si substrate,” J. Appl. Phys. 98(1), 013501 (2005).
[Crossref]

J. Liu, D. D. Cannon, K. Wada, Y. Ishikawa, D. T. Danielson, S. Jongthammanurak, J. Michel, and L. C. Kimerling, “Deformation potential constants of biaxially tensile strained Ge epitaxial films on Si(100),” Phys. Rev. B 70(15), 155309 (2004).
[Crossref]

Lo, G.

L. Ding, T. Liow, E. Lim, N. Duan, M. Yu, and G. Lo, “Ge waveguide photodetectors with responsivity roll-off beyond 1620 nm using localized stressor,” OFC/NFOEC Tech. Digest, OW3G.4, 1–3 (2012)

Lo, G. Q.

Micheal, J.

Y. Ishikawa, K. Wada, J. Liu, D. D. Cannon, H. Liao, J. Micheal, and L. C. Kimerling, “Strain-induced enhancement of near-infrared absorption in Ge epitaxial layers grown on Si substrate,” J. Appl. Phys. 98(1), 013501 (2005).
[Crossref]

Michel, J.

J. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, “Waveguide- integrated ultralow-energy GeSi electro-absorption modulators,” Nat. Photonics 2(7), 433–437 (2008).
[Crossref]

S. Jongthammanurak, J. Liu, K. Wada, D. D. Cannon, D. T. Danielson, D. Pan, L. C. Kimerling, and J. Michel, “Large electro-optic effect in tensile strained Ge-on-Si films,” Appl. Phys. Lett. 89(16), 161115 (2006).
[Crossref]

J. Liu, D. D. Cannon, K. Wada, Y. Ishikawa, D. T. Danielson, S. Jongthammanurak, J. Michel, and L. C. Kimerling, “Deformation potential constants of biaxially tensile strained Ge epitaxial films on Si(100),” Phys. Rev. B 70(15), 155309 (2004).
[Crossref]

Nakanishi, T.

A. Ogura, H. Saitoh, D. Kosemura, Y. Kakemura, T. Yoshida, M. Takei, T. Koganezawa, I. Hirosawa, M. Kohno, T. Nishita, and T. Nakanishi, “Evaluation and control of Strain in Si induced by patterned SiN stressor,” Electrochem. Solid-State Lett. 12(4), H117–H119 (2009).
[Crossref]

Nishita, T.

A. Ogura, H. Saitoh, D. Kosemura, Y. Kakemura, T. Yoshida, M. Takei, T. Koganezawa, I. Hirosawa, M. Kohno, T. Nishita, and T. Nakanishi, “Evaluation and control of Strain in Si induced by patterned SiN stressor,” Electrochem. Solid-State Lett. 12(4), H117–H119 (2009).
[Crossref]

Ogura, A.

A. Ogura, H. Saitoh, D. Kosemura, Y. Kakemura, T. Yoshida, M. Takei, T. Koganezawa, I. Hirosawa, M. Kohno, T. Nishita, and T. Nakanishi, “Evaluation and control of Strain in Si induced by patterned SiN stressor,” Electrochem. Solid-State Lett. 12(4), H117–H119 (2009).
[Crossref]

Osaka, J.

Pan, D.

S. Jongthammanurak, J. Liu, K. Wada, D. D. Cannon, D. T. Danielson, D. Pan, L. C. Kimerling, and J. Michel, “Large electro-optic effect in tensile strained Ge-on-Si films,” Appl. Phys. Lett. 89(16), 161115 (2006).
[Crossref]

Park, S. B.

Pollak, F. H.

H. Shen and F. H. Pollak, “Generalized Franz-Keldysh theory of electromodulation,” Phys. Rev. B Condens. Matter 42(11), 7097–7102 (1990).
[Crossref] [PubMed]

Pomerene, A.

J. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, “Waveguide- integrated ultralow-energy GeSi electro-absorption modulators,” Nat. Photonics 2(7), 433–437 (2008).
[Crossref]

Qing, F.

Saitoh, H.

A. Ogura, H. Saitoh, D. Kosemura, Y. Kakemura, T. Yoshida, M. Takei, T. Koganezawa, I. Hirosawa, M. Kohno, T. Nishita, and T. Nakanishi, “Evaluation and control of Strain in Si induced by patterned SiN stressor,” Electrochem. Solid-State Lett. 12(4), H117–H119 (2009).
[Crossref]

Shen, H.

H. Shen and F. H. Pollak, “Generalized Franz-Keldysh theory of electromodulation,” Phys. Rev. B Condens. Matter 42(11), 7097–7102 (1990).
[Crossref] [PubMed]

Sun, R.

J. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, “Waveguide- integrated ultralow-energy GeSi electro-absorption modulators,” Nat. Photonics 2(7), 433–437 (2008).
[Crossref]

Takei, M.

A. Ogura, H. Saitoh, D. Kosemura, Y. Kakemura, T. Yoshida, M. Takei, T. Koganezawa, I. Hirosawa, M. Kohno, T. Nishita, and T. Nakanishi, “Evaluation and control of Strain in Si induced by patterned SiN stressor,” Electrochem. Solid-State Lett. 12(4), H117–H119 (2009).
[Crossref]

Takita, S.

Tsuchizawa, T.

R. Kuroyanagi, Y. Ishikawa, T. Tsuchizawa, S. Itabashi, and K. Wada, “Controlling strain in Ge on Si for EA modulators,” Proc. IEEE GFP8, 211–213 (2011).
[Crossref]

Van de Walle, C. G.

C. G. Van de Walle, “Band lineups and deformation potentials in the model-solid theory,” Phys. Rev. B Condens. Matter 39(3), 1871–1883 (1989).
[Crossref] [PubMed]

Wada, K.

S. B. Park, S. Takita, Y. Ishikawa, J. Osaka, and K. Wada, “Reserve current reduction of Ge photodiodes on Si without post-growth annealing,” Chin. Opt. Lett. 7(4), 286–290 (2009).
[Crossref]

S. Jongthammanurak, J. Liu, K. Wada, D. D. Cannon, D. T. Danielson, D. Pan, L. C. Kimerling, and J. Michel, “Large electro-optic effect in tensile strained Ge-on-Si films,” Appl. Phys. Lett. 89(16), 161115 (2006).
[Crossref]

Y. Ishikawa, K. Wada, J. Liu, D. D. Cannon, H. Liao, J. Micheal, and L. C. Kimerling, “Strain-induced enhancement of near-infrared absorption in Ge epitaxial layers grown on Si substrate,” J. Appl. Phys. 98(1), 013501 (2005).
[Crossref]

J. Liu, D. D. Cannon, K. Wada, Y. Ishikawa, D. T. Danielson, S. Jongthammanurak, J. Michel, and L. C. Kimerling, “Deformation potential constants of biaxially tensile strained Ge epitaxial films on Si(100),” Phys. Rev. B 70(15), 155309 (2004).
[Crossref]

R. Kuroyanagi, Y. Ishikawa, T. Tsuchizawa, S. Itabashi, and K. Wada, “Controlling strain in Ge on Si for EA modulators,” Proc. IEEE GFP8, 211–213 (2011).
[Crossref]

Yoshida, T.

A. Ogura, H. Saitoh, D. Kosemura, Y. Kakemura, T. Yoshida, M. Takei, T. Koganezawa, I. Hirosawa, M. Kohno, T. Nishita, and T. Nakanishi, “Evaluation and control of Strain in Si induced by patterned SiN stressor,” Electrochem. Solid-State Lett. 12(4), H117–H119 (2009).
[Crossref]

Yu, M.

A. E. Lim, T. Y. Liow, F. Qing, N. Duan, L. Ding, M. Yu, G. Q. Lo, and D. L. Kwong, “Novel evanescent-coupled germanium electro-absorption modulator featuring monolithic integration with germanium p-i-n photodetector,” Opt. Express 19(6), 5040–5046 (2011).
[Crossref] [PubMed]

L. Ding, T. Liow, E. Lim, N. Duan, M. Yu, and G. Lo, “Ge waveguide photodetectors with responsivity roll-off beyond 1620 nm using localized stressor,” OFC/NFOEC Tech. Digest, OW3G.4, 1–3 (2012)

Yu, M. B.

Appl. Phys. Lett. (1)

S. Jongthammanurak, J. Liu, K. Wada, D. D. Cannon, D. T. Danielson, D. Pan, L. C. Kimerling, and J. Michel, “Large electro-optic effect in tensile strained Ge-on-Si films,” Appl. Phys. Lett. 89(16), 161115 (2006).
[Crossref]

Chin. Opt. Lett. (1)

Electrochem. Solid-State Lett. (1)

A. Ogura, H. Saitoh, D. Kosemura, Y. Kakemura, T. Yoshida, M. Takei, T. Koganezawa, I. Hirosawa, M. Kohno, T. Nishita, and T. Nakanishi, “Evaluation and control of Strain in Si induced by patterned SiN stressor,” Electrochem. Solid-State Lett. 12(4), H117–H119 (2009).
[Crossref]

J. Appl. Phys. (1)

Y. Ishikawa, K. Wada, J. Liu, D. D. Cannon, H. Liao, J. Micheal, and L. C. Kimerling, “Strain-induced enhancement of near-infrared absorption in Ge epitaxial layers grown on Si substrate,” J. Appl. Phys. 98(1), 013501 (2005).
[Crossref]

Nat. Photonics (1)

J. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, “Waveguide- integrated ultralow-energy GeSi electro-absorption modulators,” Nat. Photonics 2(7), 433–437 (2008).
[Crossref]

Opt. Express (2)

Phys. Rev. B (1)

J. Liu, D. D. Cannon, K. Wada, Y. Ishikawa, D. T. Danielson, S. Jongthammanurak, J. Michel, and L. C. Kimerling, “Deformation potential constants of biaxially tensile strained Ge epitaxial films on Si(100),” Phys. Rev. B 70(15), 155309 (2004).
[Crossref]

Phys. Rev. B Condens. Matter (2)

C. G. Van de Walle, “Band lineups and deformation potentials in the model-solid theory,” Phys. Rev. B Condens. Matter 39(3), 1871–1883 (1989).
[Crossref] [PubMed]

H. Shen and F. H. Pollak, “Generalized Franz-Keldysh theory of electromodulation,” Phys. Rev. B Condens. Matter 42(11), 7097–7102 (1990).
[Crossref] [PubMed]

Other (2)

R. Kuroyanagi, Y. Ishikawa, T. Tsuchizawa, S. Itabashi, and K. Wada, “Controlling strain in Ge on Si for EA modulators,” Proc. IEEE GFP8, 211–213 (2011).
[Crossref]

L. Ding, T. Liow, E. Lim, N. Duan, M. Yu, and G. Lo, “Ge waveguide photodetectors with responsivity roll-off beyond 1620 nm using localized stressor,” OFC/NFOEC Tech. Digest, OW3G.4, 1–3 (2012)

Cited By

OSA participates in Crossref's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (5)

Fig. 1
Fig. 1 The theoretical relationship of the absorption edge of Ge with applied stress along [010] on Ge(100).
Fig. 2
Fig. 2 (a) The schematics of cross-section of the strained Ge photodetector and the reference photodetector. (b) The stress profile of the strained Ge photodetector.
Fig. 3
Fig. 3 The responsitivity spectra of free space Ge photodetectors with and without stressors.
Fig. 4
Fig. 4 The responsivity spectra of free space Ge photodetectors with SiNx stressors.
Fig. 5
Fig. 5 (a) The electric field profile of the Ge photodetector with stressors. The depth profile is calculated using P and B profiles of the Ge epilayer. (b) Figure of merit Δα/α at wavelength of 1640 nm as a function of applied reverse bias.

Equations (2)

Equations on this page are rendered with MathJax. Learn more.

Δα α (exp)= (α(V)α(0)) α(0) × t i t ,
Δα α (real)= Δα α (exp)× t t i ,

Metrics