Abstract

The effects of photo-related stress on the electrical performances of a-SiGe:H thin-film transistors (TFTs) were investigated in comparison with a-Si:H TFTs. Compared with a-Si:H TFTs, the a-SiGe:H TFTs show better stability to the light stress because the number of electrons involved in the creation of dangling bonds are smaller in a-SiGe:H TFTs, resulting in less light-induced degradation. However, a larger threshold voltage shift from the positive gate bias was observed due to the higher number of weak bonds in a-SiGe:H TFTs, which leads to a higher gate bias instability than is observed for a-Si:H TFTs. The temperature dependences of the electrical properties in a-SiGe:H TFTs were observed, and they indicated that a-SiGe:H TFTs follow a thermally activated behavior pattern. Based on the thermally activated behavior, a new model predicting the lifetime of a-SiGe:H TFT image sensors was proposed. The instability of the drain current with respect to the stress time under an electrical bias and light was estimated. Based on the calculated lifetime, the a-SiGe:H TFTs are predicted to be reliable for long-term applications in image sensors.

© 2012 IEEE

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  1. S. Aljishi, Z. E. Smith, D. Slobodin, J. Kolodzey, V. Chu, R. Schwarz, S. Wagner, "Electronic transport and the density of states distribution in a-(Si, Ge):H, F alloys," Mat. Res. Symp. Proc. (1986) pp. 269-274.
  2. A. Catalano, R. R. Arya, B. Fieselmann, B. Goldstein, J. Newton, S. Wiedeman, M. Bennett, D. E. Carlson, "Solar cells: Present status and future prospects," J. Non-Cryst. Solids 115, 14-20 (1989).
  3. D. S. Shen, J. P. Conde, V. Chu, S. Aljishi, J. Z. Liu, S. Wagner, "Amorphous silicon-germanium thin-film photodetector array," IEEE Electron Device Lett. 13, 5-7 (1992).
  4. S. D. Liu, S. C. Lee, M. Y. Chern, "Hydrogenated amorphous silicon-germanium PIN X-ray detector," IEEE Trans. Electron Devices 48, 1564-1567 (2001).
  5. J.-J. Ho, Y. K. Fang, K.-H. Wu, W. T. Hsieh, S. C. Huang, G. S. Chen, M. S. Ju, J.-J. Lin, "High-speed amorphous silicon germanium infrared sensors prepared on crystalline silicon substrates," IEEE Trans. Electron Devices 45, 2085-2088 (1998).
  6. S. Y. Han, D. C. Kim, B. Cho, K. S. Jeon, S. M. Seo, M. S. Seo, S.-W. Jung, K. Jeong, W. K. Kim, S.-H. Yang, N.-H. Kim, J. Song, H.-S. Kong, H. G. Kim, "A highly sensitive and low-noise IR photosensor based on a-SiGe as a sensing and noise filter: Toward large-sized touch-screen LCD panels," J. Soc. Inf. Display 19, 855-860 (2011).
  7. C. Y. Huang, J.-W. Tsai, T.-H. Teng, C. J. Yang, H.-C. Cheng, "Turnaround phenomenon of threshold voltage shifts in amorphous silicon thin film transistors under negative bias stress," Jpn. J. Appl. Phys. 39, 5763-5766 (2000).
  8. M. J. Powel, C. van Berkel, I. D. French, D. H. Nichoils, "Bias dependence of instability mechanisms in amorphous silicon thin-film transistors," Appl. Phys. Letts. 51, 1242-1244 (1987).
  9. M. J. Powel, C. van Berkel, J. R. Hughes, "Time and temperature dependence of instability mechanisms in amorphous silicon thin-film transistors," Appl. Phys. Letts. 54, 1323-1325 (1989).
  10. C.-S. Chiang, J. Kanicki, K. Takechi, "Electrical instability of hydrogenated amorphous silicon thin-film transistors for active-matrix liquid-crystal displays," Jpn. J. Appl. Phys. 37, 4704-4710 (1989).
  11. A. V. Gelatos, J. Kanicki, "Bias stress-induced instabilities in amorphous silicon nitride/hydrogenated amorphous silicon structures: Is the “carrier-induced defect creation” model correct?," Appl. Phys. Lett. 57, 1197-1199 (1990).
  12. S. C. Deane, F. J. Clough, W. I. Milne, M. J. Powel, "Bias-stress-induced creation and removal of dangling-bond states in amorphous silicon thin-film transistors," Appl. Phys. Lett. 60, 207-209 (1992).
  13. W. B. Jackson, M. D. Moyer, "Creation of near-interface defects in hydrogenated amorphous silicon-silicon nitride heterojunctions: The role of hydrogen," Phys. Rev. B 36, 6217-6220 (1987).
  14. S. Hazra, A. R. Middya, S. Ray, "Reduction of light-induced metastable changes in a-SiGe:H prepared by using helium dilution: Comparison of metastability of helium- and hydrogen-diluted a-SiGe:H alloys," J. Phys D: Appl. Phys. 30, 325-329 (1997).
  15. J. Tauc, A. Grigorovici, A. Vancu, "Optical properties and electronic structure of amorphous germanium," Phys. Status Solidi (b) 15, 627-637 (1966).
  16. T. Pisarkiewicz, A. Kolodziej, E. Schabowska-Osiowska, T. Stapinski, A. Rodzik, P. Rava, "Density of states in the pseudo-gap of amorphous silicon-germanium alloys from electrical and optical measurements," Appl. Phys. Lett. 60, 1465-1467 (1992).
  17. W. Beyer, H. Wagner, F. Finger, "Hydrogen evolution from a-Si:C:H and a-Si:Ge:H alloys," J. Non-Cryst. Solids 77/78, 857-860 (1985).
  18. C. R. Kagan, P. Andry, Thin Film Transistors (Marcel Dekker, 2003).
  19. S. Y. Han, K. S. Jeon, B. Cho, M. S. Seo, J. Song, H.-S. Kong, "Characteristics of a-SiGe:H thin film transistor infrared photosensor for touch sensing display," IEEE J. Quantum Electron. 48, 952-959 (2012).
  20. M. Güneş, M. E. D. Yavas, J. Klomfass, F. Finger, "The effects of native and light induced defects on optoelectronic properties of hydrogenated amorphous silicon–germanium (a-SiGe:H) alloy thin films," J. Mater. Sci: Mater Electron. 21, 153-159 (2009).
  21. J. D. Cohen, Amorphous Silicon and its Alloys (INSPEC, 1998).
  22. A. Ralland, J. Richard, J. P. Kleider, D. Mencaraglia, "Electrical properties of amorphous silicon transistors and MIS-devices: Comparative study of top nitride and bottom nitride configurations," J. Electrochem. Soc. 140, 3679-3683 (1993).
  23. M. Stutzmann, W. B. Jackson, C. C. Tsai, "Light-induced metastable defects in hydrogenated amorphous silicon: A systematic study," Phys. Rev. B 32, 23-47 (1984).
  24. R. M. A. Dawson, C. M. Fortmann, "The Staebler-Wronski effect and the thermal equilibration of defect and free carrier concentrations," J. Appl. Phys. 79, 3075-3081 (1996).
  25. S. Guha, "Light-induced effects in amorphous silicon alloys – Design of solar cells with improved stability," J. Non-Cryst. Solids 77/78, 1451-1460 (1985).
  26. K. Nakagawa, M. Fukaya, T. Shoji, K. Sakai, T. Komatsu, "Stability and new structure in a-Si:H photoconductive sensors," J. Non-Cryst. Solids 59/60, 1199-1202 (1983).
  27. P. G. LeComber, W. E. Spear, "Electronic transport in amorphous silicon films," Phys. Rev. Lett. 25, 509-511 (1970).
  28. A. Kuo, T. K. Won, J. Kanicki, "Advanced amorphous silicon thin-film transistors for AM-OLEDs: Electrical performance and stability," IEEE Trans. Electron Devices 55, 1621-1629 (2007).
  29. S. Y. Han, K. T. Park, H. S. Jeon, Y. W. Heo, B. S. Bae, "Optical properties of a-SiGe:H thin film transistor for infrared image sensors in touch sensing display," J. Display Technol. 8, 617-622 (2012).

2012

S. Y. Han, K. S. Jeon, B. Cho, M. S. Seo, J. Song, H.-S. Kong, "Characteristics of a-SiGe:H thin film transistor infrared photosensor for touch sensing display," IEEE J. Quantum Electron. 48, 952-959 (2012).

S. Y. Han, K. T. Park, H. S. Jeon, Y. W. Heo, B. S. Bae, "Optical properties of a-SiGe:H thin film transistor for infrared image sensors in touch sensing display," J. Display Technol. 8, 617-622 (2012).

2011

S. Y. Han, D. C. Kim, B. Cho, K. S. Jeon, S. M. Seo, M. S. Seo, S.-W. Jung, K. Jeong, W. K. Kim, S.-H. Yang, N.-H. Kim, J. Song, H.-S. Kong, H. G. Kim, "A highly sensitive and low-noise IR photosensor based on a-SiGe as a sensing and noise filter: Toward large-sized touch-screen LCD panels," J. Soc. Inf. Display 19, 855-860 (2011).

2009

M. Güneş, M. E. D. Yavas, J. Klomfass, F. Finger, "The effects of native and light induced defects on optoelectronic properties of hydrogenated amorphous silicon–germanium (a-SiGe:H) alloy thin films," J. Mater. Sci: Mater Electron. 21, 153-159 (2009).

2007

A. Kuo, T. K. Won, J. Kanicki, "Advanced amorphous silicon thin-film transistors for AM-OLEDs: Electrical performance and stability," IEEE Trans. Electron Devices 55, 1621-1629 (2007).

2001

S. D. Liu, S. C. Lee, M. Y. Chern, "Hydrogenated amorphous silicon-germanium PIN X-ray detector," IEEE Trans. Electron Devices 48, 1564-1567 (2001).

2000

C. Y. Huang, J.-W. Tsai, T.-H. Teng, C. J. Yang, H.-C. Cheng, "Turnaround phenomenon of threshold voltage shifts in amorphous silicon thin film transistors under negative bias stress," Jpn. J. Appl. Phys. 39, 5763-5766 (2000).

1998

J.-J. Ho, Y. K. Fang, K.-H. Wu, W. T. Hsieh, S. C. Huang, G. S. Chen, M. S. Ju, J.-J. Lin, "High-speed amorphous silicon germanium infrared sensors prepared on crystalline silicon substrates," IEEE Trans. Electron Devices 45, 2085-2088 (1998).

1997

S. Hazra, A. R. Middya, S. Ray, "Reduction of light-induced metastable changes in a-SiGe:H prepared by using helium dilution: Comparison of metastability of helium- and hydrogen-diluted a-SiGe:H alloys," J. Phys D: Appl. Phys. 30, 325-329 (1997).

1996

R. M. A. Dawson, C. M. Fortmann, "The Staebler-Wronski effect and the thermal equilibration of defect and free carrier concentrations," J. Appl. Phys. 79, 3075-3081 (1996).

1993

A. Ralland, J. Richard, J. P. Kleider, D. Mencaraglia, "Electrical properties of amorphous silicon transistors and MIS-devices: Comparative study of top nitride and bottom nitride configurations," J. Electrochem. Soc. 140, 3679-3683 (1993).

1992

S. C. Deane, F. J. Clough, W. I. Milne, M. J. Powel, "Bias-stress-induced creation and removal of dangling-bond states in amorphous silicon thin-film transistors," Appl. Phys. Lett. 60, 207-209 (1992).

D. S. Shen, J. P. Conde, V. Chu, S. Aljishi, J. Z. Liu, S. Wagner, "Amorphous silicon-germanium thin-film photodetector array," IEEE Electron Device Lett. 13, 5-7 (1992).

T. Pisarkiewicz, A. Kolodziej, E. Schabowska-Osiowska, T. Stapinski, A. Rodzik, P. Rava, "Density of states in the pseudo-gap of amorphous silicon-germanium alloys from electrical and optical measurements," Appl. Phys. Lett. 60, 1465-1467 (1992).

1990

A. V. Gelatos, J. Kanicki, "Bias stress-induced instabilities in amorphous silicon nitride/hydrogenated amorphous silicon structures: Is the “carrier-induced defect creation” model correct?," Appl. Phys. Lett. 57, 1197-1199 (1990).

1989

A. Catalano, R. R. Arya, B. Fieselmann, B. Goldstein, J. Newton, S. Wiedeman, M. Bennett, D. E. Carlson, "Solar cells: Present status and future prospects," J. Non-Cryst. Solids 115, 14-20 (1989).

M. J. Powel, C. van Berkel, J. R. Hughes, "Time and temperature dependence of instability mechanisms in amorphous silicon thin-film transistors," Appl. Phys. Letts. 54, 1323-1325 (1989).

C.-S. Chiang, J. Kanicki, K. Takechi, "Electrical instability of hydrogenated amorphous silicon thin-film transistors for active-matrix liquid-crystal displays," Jpn. J. Appl. Phys. 37, 4704-4710 (1989).

1987

M. J. Powel, C. van Berkel, I. D. French, D. H. Nichoils, "Bias dependence of instability mechanisms in amorphous silicon thin-film transistors," Appl. Phys. Letts. 51, 1242-1244 (1987).

W. B. Jackson, M. D. Moyer, "Creation of near-interface defects in hydrogenated amorphous silicon-silicon nitride heterojunctions: The role of hydrogen," Phys. Rev. B 36, 6217-6220 (1987).

1985

W. Beyer, H. Wagner, F. Finger, "Hydrogen evolution from a-Si:C:H and a-Si:Ge:H alloys," J. Non-Cryst. Solids 77/78, 857-860 (1985).

S. Guha, "Light-induced effects in amorphous silicon alloys – Design of solar cells with improved stability," J. Non-Cryst. Solids 77/78, 1451-1460 (1985).

1984

M. Stutzmann, W. B. Jackson, C. C. Tsai, "Light-induced metastable defects in hydrogenated amorphous silicon: A systematic study," Phys. Rev. B 32, 23-47 (1984).

1983

K. Nakagawa, M. Fukaya, T. Shoji, K. Sakai, T. Komatsu, "Stability and new structure in a-Si:H photoconductive sensors," J. Non-Cryst. Solids 59/60, 1199-1202 (1983).

1970

P. G. LeComber, W. E. Spear, "Electronic transport in amorphous silicon films," Phys. Rev. Lett. 25, 509-511 (1970).

1966

J. Tauc, A. Grigorovici, A. Vancu, "Optical properties and electronic structure of amorphous germanium," Phys. Status Solidi (b) 15, 627-637 (1966).

Appl. Phys. Letts.

M. J. Powel, C. van Berkel, I. D. French, D. H. Nichoils, "Bias dependence of instability mechanisms in amorphous silicon thin-film transistors," Appl. Phys. Letts. 51, 1242-1244 (1987).

Appl. Phys. Lett.

A. V. Gelatos, J. Kanicki, "Bias stress-induced instabilities in amorphous silicon nitride/hydrogenated amorphous silicon structures: Is the “carrier-induced defect creation” model correct?," Appl. Phys. Lett. 57, 1197-1199 (1990).

S. C. Deane, F. J. Clough, W. I. Milne, M. J. Powel, "Bias-stress-induced creation and removal of dangling-bond states in amorphous silicon thin-film transistors," Appl. Phys. Lett. 60, 207-209 (1992).

T. Pisarkiewicz, A. Kolodziej, E. Schabowska-Osiowska, T. Stapinski, A. Rodzik, P. Rava, "Density of states in the pseudo-gap of amorphous silicon-germanium alloys from electrical and optical measurements," Appl. Phys. Lett. 60, 1465-1467 (1992).

Appl. Phys. Letts.

M. J. Powel, C. van Berkel, J. R. Hughes, "Time and temperature dependence of instability mechanisms in amorphous silicon thin-film transistors," Appl. Phys. Letts. 54, 1323-1325 (1989).

IEEE J. Quantum Electron.

S. Y. Han, K. S. Jeon, B. Cho, M. S. Seo, J. Song, H.-S. Kong, "Characteristics of a-SiGe:H thin film transistor infrared photosensor for touch sensing display," IEEE J. Quantum Electron. 48, 952-959 (2012).

IEEE Trans. Electron Devices

J.-J. Ho, Y. K. Fang, K.-H. Wu, W. T. Hsieh, S. C. Huang, G. S. Chen, M. S. Ju, J.-J. Lin, "High-speed amorphous silicon germanium infrared sensors prepared on crystalline silicon substrates," IEEE Trans. Electron Devices 45, 2085-2088 (1998).

IEEE Electron Device Lett.

D. S. Shen, J. P. Conde, V. Chu, S. Aljishi, J. Z. Liu, S. Wagner, "Amorphous silicon-germanium thin-film photodetector array," IEEE Electron Device Lett. 13, 5-7 (1992).

IEEE Trans. Electron Devices

S. D. Liu, S. C. Lee, M. Y. Chern, "Hydrogenated amorphous silicon-germanium PIN X-ray detector," IEEE Trans. Electron Devices 48, 1564-1567 (2001).

A. Kuo, T. K. Won, J. Kanicki, "Advanced amorphous silicon thin-film transistors for AM-OLEDs: Electrical performance and stability," IEEE Trans. Electron Devices 55, 1621-1629 (2007).

J. Phys D: Appl. Phys.

S. Hazra, A. R. Middya, S. Ray, "Reduction of light-induced metastable changes in a-SiGe:H prepared by using helium dilution: Comparison of metastability of helium- and hydrogen-diluted a-SiGe:H alloys," J. Phys D: Appl. Phys. 30, 325-329 (1997).

J. Appl. Phys.

R. M. A. Dawson, C. M. Fortmann, "The Staebler-Wronski effect and the thermal equilibration of defect and free carrier concentrations," J. Appl. Phys. 79, 3075-3081 (1996).

J. Display Technol.

J. Electrochem. Soc.

A. Ralland, J. Richard, J. P. Kleider, D. Mencaraglia, "Electrical properties of amorphous silicon transistors and MIS-devices: Comparative study of top nitride and bottom nitride configurations," J. Electrochem. Soc. 140, 3679-3683 (1993).

J. Mater. Sci: Mater Electron.

M. Güneş, M. E. D. Yavas, J. Klomfass, F. Finger, "The effects of native and light induced defects on optoelectronic properties of hydrogenated amorphous silicon–germanium (a-SiGe:H) alloy thin films," J. Mater. Sci: Mater Electron. 21, 153-159 (2009).

J. Non-Cryst. Solids

W. Beyer, H. Wagner, F. Finger, "Hydrogen evolution from a-Si:C:H and a-Si:Ge:H alloys," J. Non-Cryst. Solids 77/78, 857-860 (1985).

A. Catalano, R. R. Arya, B. Fieselmann, B. Goldstein, J. Newton, S. Wiedeman, M. Bennett, D. E. Carlson, "Solar cells: Present status and future prospects," J. Non-Cryst. Solids 115, 14-20 (1989).

S. Guha, "Light-induced effects in amorphous silicon alloys – Design of solar cells with improved stability," J. Non-Cryst. Solids 77/78, 1451-1460 (1985).

K. Nakagawa, M. Fukaya, T. Shoji, K. Sakai, T. Komatsu, "Stability and new structure in a-Si:H photoconductive sensors," J. Non-Cryst. Solids 59/60, 1199-1202 (1983).

J. Soc. Inf. Display

S. Y. Han, D. C. Kim, B. Cho, K. S. Jeon, S. M. Seo, M. S. Seo, S.-W. Jung, K. Jeong, W. K. Kim, S.-H. Yang, N.-H. Kim, J. Song, H.-S. Kong, H. G. Kim, "A highly sensitive and low-noise IR photosensor based on a-SiGe as a sensing and noise filter: Toward large-sized touch-screen LCD panels," J. Soc. Inf. Display 19, 855-860 (2011).

Jpn. J. Appl. Phys.

C. Y. Huang, J.-W. Tsai, T.-H. Teng, C. J. Yang, H.-C. Cheng, "Turnaround phenomenon of threshold voltage shifts in amorphous silicon thin film transistors under negative bias stress," Jpn. J. Appl. Phys. 39, 5763-5766 (2000).

C.-S. Chiang, J. Kanicki, K. Takechi, "Electrical instability of hydrogenated amorphous silicon thin-film transistors for active-matrix liquid-crystal displays," Jpn. J. Appl. Phys. 37, 4704-4710 (1989).

Phys. Rev. B

M. Stutzmann, W. B. Jackson, C. C. Tsai, "Light-induced metastable defects in hydrogenated amorphous silicon: A systematic study," Phys. Rev. B 32, 23-47 (1984).

Phys. Rev. B

W. B. Jackson, M. D. Moyer, "Creation of near-interface defects in hydrogenated amorphous silicon-silicon nitride heterojunctions: The role of hydrogen," Phys. Rev. B 36, 6217-6220 (1987).

Phys. Rev. Lett.

P. G. LeComber, W. E. Spear, "Electronic transport in amorphous silicon films," Phys. Rev. Lett. 25, 509-511 (1970).

Phys. Status Solidi (b)

J. Tauc, A. Grigorovici, A. Vancu, "Optical properties and electronic structure of amorphous germanium," Phys. Status Solidi (b) 15, 627-637 (1966).

Other

C. R. Kagan, P. Andry, Thin Film Transistors (Marcel Dekker, 2003).

J. D. Cohen, Amorphous Silicon and its Alloys (INSPEC, 1998).

S. Aljishi, Z. E. Smith, D. Slobodin, J. Kolodzey, V. Chu, R. Schwarz, S. Wagner, "Electronic transport and the density of states distribution in a-(Si, Ge):H, F alloys," Mat. Res. Symp. Proc. (1986) pp. 269-274.

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