Design, fabrication, and modeling of high-speed metal-semiconductor-metal (MSM) photodetectors with indium-tin-oxide (ITO) and Ti/Pt/Au contacts

Christian Beaulieu; Francois L. Gouin; Julian P. Noad; William Hartman; Ewa Lisicka-Skrzek; Karen A. Vineberg; Ezio Berolo

doi:10.1117/12.206898

24 April 1995 Design, fabrication, and modeling of high-speed metal-semiconductor-metal (MSM) photodetectors with indium-tin-oxide (ITO) and Ti/Pt/Au contacts

Christian Beaulieu, Francois L. Gouin, Julian P. Noad, William Hartman, Ewa Lisicka-Skrzek, Karen A. Vineberg, Ezio Berolo

Author Affiliations +

Proceedings Volume 2397, Optoelectronic Integrated Circuit Materials, Physics, and Devices; (1995) https://doi.org/10.1117/12.206898
Event: Photonics West '95, 1995, San Jose, CA, United States

Abstract

Metal-semiconductor-metal photodetectors have been fabricated on undoped epitaxial GaAs material with gold and indium-tin-oxide interdigitated contacts. In both cases, various electrode configurations were laid out with combinations of finger spacings and finger widths ranging from 1 to 3 micrometers and detector cross-sections of 25 X 25, 50 X 50 and 100 X 100 micrometers ². Frequency response measurements were carried out up to 20 GHz using a high-speed electro-optic modulator combined with a DC-operated laser diode and an ultrafast photodetector for system calibration. This frequency domain technique ensures accurate measurement of true analog bandwidth compared to time-domain techniques which can easily lead to an overestimation of photodetector bandwidth. Photodetector responsivity has been plotted as a function of bias voltage. We note that for similar devices, Ti/Pt/Au contact MSMs require lower bias voltages before they reach their saturation bandwidth than ITO contact MSMs. For a 100 X 100 micrometers ² ITO MSM with a 2 micrometers finger width and a 2 micrometers finger spacing, the 3 dB bandwidth was measured to be 4 GHz at 10 V bias. By comparison, similar gold contact MSMs exhibit 3 dB bandwidths in excess of 12 GHz. The difference in speed is partly explained by the higher device parasitics of the ITO MSMs, as confirmed by S₁₁ measurements made on both types of device. The S₁₁ data was also used to extract the MSM equivalent circuit parameters for a high-frequency MSM model. Similar measurements on other electrode configurations show that as expected, the speed of ITO MSMs become considerably higher as device size is decreased, until the limit where transmit-time effects start to dominate the overall performance.

Citation Download Citation

Christian Beaulieu, Francois L. Gouin, Julian P. Noad, William Hartman, Ewa Lisicka-Skrzek, Karen A. Vineberg, and Ezio Berolo "Design, fabrication, and modeling of high-speed metal-semiconductor-metal (MSM) photodetectors with indium-tin-oxide (ITO) and Ti/Pt/Au contacts", Proc. SPIE 2397, Optoelectronic Integrated Circuit Materials, Physics, and Devices, (24 April 1995); https://doi.org/10.1117/12.206898

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available