Hostname: page-component-745bb68f8f-kw2vx Total loading time: 0 Render date: 2025-02-09T01:02:07.190Z Has data issue: false hasContentIssue false
  • English
  • Français

Performance of Photo-Transistors with thin (50 nm.) a-Si:H Layers

Published online by Cambridge University Press:  15 February 2011

Serag M. GadelRab  and
Savvas G. Chamberlain
Serag M. GadelRab
Affiliation:
University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, Ontario, Canada N2L 3G1.
Savvas G. Chamberlain
Affiliation:
University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, Ontario, Canada N2L 3G1.
Get access

Abstract

Photo-transistor based a-Si:H image sensors allow the integration of photo-elements and pixel circuitry using standard TFT fabrication processes. While pixel circuitry use thin a-Si:H films (≈ 0.05μm) to minimize the contact resistance, photo-transistors require thick a-Si:H films (≈0.5μm) to maximize photo-sensitivity. We fabricated a new, high sensitivity photo-transistor structure using 0.05μ a-Si:H films. High optical sensitivity is achieved by separating the conduction paths of photo-generated electrons and holes using a secondary gate. Further, the optical path within the photo-transistor is doubled through manipulation of device layout. The photo-transistor show an Ilight/Idarkratio in excess of 103.

We compared the transient behavior of conventional and high-sensitivity photo-transistors. We found that both devices display an increase in current with time when biased in either the dark or illuminated conditions. The current increases by six orders of magnitudes then saturates within 200 seconds of bias application. Experiments indicate that this transient behavior is due to a rise in the conductivity of the gap region with time; measurements on 0.05μm thick photo-resistor structures showed that their current increases with time. The shape and temporal range of this behavior rules out the presence of parasitic capacitive effects.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 377: Symposium A – Amorphous Silicon Technology 1995 , 1995 , 713
Copyright
Copyright © Materials Research Society 1995

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

[1] GadelRab, S. M. and Chamberlain, S. G., Mat. Res. Soc. Symp. Proc., 336, pp. 835–840, (1994).Google Scholar
[2] GadelRab, S. M. and Chamberlain, S. G., IEEE Trans. Elect. Devices, 41, pp 462–464, (1994).Google Scholar
[3] Kaneko, Y., Koike, N., Tsutsui, K. and Tsukada, T., Appl. Phys. Lett., 56, pp 650–652, (1990).Google Scholar
[4] Takayama, S., Mori, K., Suzuki, K. and Tanuma, C., IEEE Trans. Elect., 40, pp 342–347, (1993).Google Scholar
[5] Yamaguchi, M., Kaneko, Y. and Tsutsui, K., Jap. J. Appl. Phys., 32, pp 458–461, (1992).Google Scholar
[6] Rosan, K., IEEE Trans. Elect. Devices, 36, pp 2923–2927, (1989).Google Scholar
[7] Johnson, N. M. and Chiang, A., Appl. Phys. Lett., 45, pp 1102–1104, (1984).Google Scholar
[8] Stutzmann, M., Phil. Mag., 56, pp 63–70, (1987).Google Scholar
[9] Miri, A. M. and Chamberlain, S. G., these proceedings.Google Scholar
[10] Street, R. A., Appl. Phys. Lett., 59, pp 1084–1086, (1991).Google Scholar