In/sub 0.53/Ga/sub 0.47/As MSM photodiodes with transparent CTO Schottky contacts and digital superlattice grading

Wei Gao; Paul R. Berger; George J. Zydzik; Henry M. O'Bryan; Deborah L. Sivco; Alfred Y. Cho

doi:10.1109/16.644632

In/sub 0.53/Ga/sub 0.47/As MSM photodiodes with transparent CTO Schottky contacts and digital superlattice grading

Wei Gao, Paul R. Berger, George J. Zydzik, Henry M. O'Bryan, Deborah L. Sivco, Alfred Y. Cho

Research output: Contribution to journal › Article › Scientific › peer-review

21 Citations (Scopus)

Abstract

Metal-semiconductor-metal (MSM) photodiodes with an In_0.53Ga_0.47As active region were investigated using a transparent cadmium tin oxide (CTO) layer for the interdigitated electrodes to improve the low responsivity of conventional MSM photodiodes with opaque electrodes. CTO is suitable as a Schottky contact an optical window and an anti-reflection (AR) coating. The transparent contact prevents shadowing of the active layer by the top electrode thus allowing greater collection of incident light. Responsivity of CTO-based MSM photodiodes with 1-μm finger widths and 2-μm finger spacings and without an AR coating between the electrodes was twice (0.62 A/W) that of a similar MSM photodiodes with Ti/Au electrodes (0.30 A/W). A thin 800 Å In_0.52Al_0.48As layer was inserted below the electrodes to elevate the electrode Schottky barrier height. A digitally graded superlattice region (660 Å) was also employed to reduce carrier trapping at the In_0.53Ga_0.47As/In_0.52Al_0.48As heterointerface which acts to degrade photodiode bandwidth. Bandwidth of opaque electrode MSM's was elevated nearly an order of magnitude over a previous MSM photodiode design with an abrupt heterointerface whereas the bandwidth of transparent electrode MSM's only improved about five times indicating resistive effects may be intervening. Publisher Item Identifier S 0018-9383(97)08292-0.

Original language	English
Pages (from-to)	2174-2179
Number of pages	6
Journal	IEEE Transactions on Electron Devices
Volume	44
Issue number	12
DOIs	https://doi.org/10.1109/16.644632
Publication status	Published - 1997
Externally published	Yes
Publication type	A1 Journal article-refereed

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Electrical and Electronic Engineering

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@article{672bb9a62f584513aa30f3f64532bad2,

title = "In/sub 0.53/Ga/sub 0.47/As MSM photodiodes with transparent CTO Schottky contacts and digital superlattice grading",

abstract = "Metal-semiconductor-metal (MSM) photodiodes with an In0.53Ga0.47As active region were investigated using a transparent cadmium tin oxide (CTO) layer for the interdigitated electrodes to improve the low responsivity of conventional MSM photodiodes with opaque electrodes. CTO is suitable as a Schottky contact an optical window and an anti-reflection (AR) coating. The transparent contact prevents shadowing of the active layer by the top electrode thus allowing greater collection of incident light. Responsivity of CTO-based MSM photodiodes with 1-μm finger widths and 2-μm finger spacings and without an AR coating between the electrodes was twice (0.62 A/W) that of a similar MSM photodiodes with Ti/Au electrodes (0.30 A/W). A thin 800 {\AA} In0.52Al0.48As layer was inserted below the electrodes to elevate the electrode Schottky barrier height. A digitally graded superlattice region (660 {\AA}) was also employed to reduce carrier trapping at the In0.53Ga0.47As/In0.52Al0.48As heterointerface which acts to degrade photodiode bandwidth. Bandwidth of opaque electrode MSM's was elevated nearly an order of magnitude over a previous MSM photodiode design with an abrupt heterointerface whereas the bandwidth of transparent electrode MSM's only improved about five times indicating resistive effects may be intervening. Publisher Item Identifier S 0018-9383(97)08292-0.",

author = "Wei Gao and Berger, {Paul R.} and Zydzik, {George J.} and O'Bryan, {Henry M.} and Sivco, {Deborah L.} and Cho, {Alfred Y.}",

note = "Funding Information: Manuscript received January 14, 1997; revised April 4, 1997. The review of this paper was arranged by Editor P. K. Bhattacharya. This work was supported in part by the University of Delaware Research Foundation (UDRF). W. Gao was with the Department of Electrical and Computer Engineering, University of Delaware, Newark, DE 19716 USA. He is now with Lasertron, Bedford, MA 01730 USA. P. R. Berger is with the Department of Electrical and Computer Engineering, University of Delaware, Newark, DE 19716 USA. G. J. Zydzik, H. M. O{\textquoteright}Bryan, D. L. Sivco, and A. Y. Cho are with Bell Laboratories, Lucent Technologies, Murray Hill, NJ 07974 USA. Publisher Item Identifier S 0018-9383(97)08292-0. Copyright: Copyright 2011 Elsevier B.V., All rights reserved.",

year = "1997",

doi = "10.1109/16.644632",

language = "English",

volume = "44",

pages = "2174--2179",

journal = "IEEE Transactions on Electron Devices",

issn = "0018-9383",

publisher = "Institute of Electrical and Electronics Engineers",

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TY - JOUR

T1 - In/sub 0.53/Ga/sub 0.47/As MSM photodiodes with transparent CTO Schottky contacts and digital superlattice grading

AU - Gao, Wei

AU - Berger, Paul R.

AU - Zydzik, George J.

AU - O'Bryan, Henry M.

AU - Sivco, Deborah L.

AU - Cho, Alfred Y.

N1 - Funding Information: Manuscript received January 14, 1997; revised April 4, 1997. The review of this paper was arranged by Editor P. K. Bhattacharya. This work was supported in part by the University of Delaware Research Foundation (UDRF). W. Gao was with the Department of Electrical and Computer Engineering, University of Delaware, Newark, DE 19716 USA. He is now with Lasertron, Bedford, MA 01730 USA. P. R. Berger is with the Department of Electrical and Computer Engineering, University of Delaware, Newark, DE 19716 USA. G. J. Zydzik, H. M. O’Bryan, D. L. Sivco, and A. Y. Cho are with Bell Laboratories, Lucent Technologies, Murray Hill, NJ 07974 USA. Publisher Item Identifier S 0018-9383(97)08292-0. Copyright: Copyright 2011 Elsevier B.V., All rights reserved.

PY - 1997

Y1 - 1997

N2 - Metal-semiconductor-metal (MSM) photodiodes with an In0.53Ga0.47As active region were investigated using a transparent cadmium tin oxide (CTO) layer for the interdigitated electrodes to improve the low responsivity of conventional MSM photodiodes with opaque electrodes. CTO is suitable as a Schottky contact an optical window and an anti-reflection (AR) coating. The transparent contact prevents shadowing of the active layer by the top electrode thus allowing greater collection of incident light. Responsivity of CTO-based MSM photodiodes with 1-μm finger widths and 2-μm finger spacings and without an AR coating between the electrodes was twice (0.62 A/W) that of a similar MSM photodiodes with Ti/Au electrodes (0.30 A/W). A thin 800 Å In0.52Al0.48As layer was inserted below the electrodes to elevate the electrode Schottky barrier height. A digitally graded superlattice region (660 Å) was also employed to reduce carrier trapping at the In0.53Ga0.47As/In0.52Al0.48As heterointerface which acts to degrade photodiode bandwidth. Bandwidth of opaque electrode MSM's was elevated nearly an order of magnitude over a previous MSM photodiode design with an abrupt heterointerface whereas the bandwidth of transparent electrode MSM's only improved about five times indicating resistive effects may be intervening. Publisher Item Identifier S 0018-9383(97)08292-0.

AB - Metal-semiconductor-metal (MSM) photodiodes with an In0.53Ga0.47As active region were investigated using a transparent cadmium tin oxide (CTO) layer for the interdigitated electrodes to improve the low responsivity of conventional MSM photodiodes with opaque electrodes. CTO is suitable as a Schottky contact an optical window and an anti-reflection (AR) coating. The transparent contact prevents shadowing of the active layer by the top electrode thus allowing greater collection of incident light. Responsivity of CTO-based MSM photodiodes with 1-μm finger widths and 2-μm finger spacings and without an AR coating between the electrodes was twice (0.62 A/W) that of a similar MSM photodiodes with Ti/Au electrodes (0.30 A/W). A thin 800 Å In0.52Al0.48As layer was inserted below the electrodes to elevate the electrode Schottky barrier height. A digitally graded superlattice region (660 Å) was also employed to reduce carrier trapping at the In0.53Ga0.47As/In0.52Al0.48As heterointerface which acts to degrade photodiode bandwidth. Bandwidth of opaque electrode MSM's was elevated nearly an order of magnitude over a previous MSM photodiode design with an abrupt heterointerface whereas the bandwidth of transparent electrode MSM's only improved about five times indicating resistive effects may be intervening. Publisher Item Identifier S 0018-9383(97)08292-0.

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DO - 10.1109/16.644632

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VL - 44

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JO - IEEE Transactions on Electron Devices

JF - IEEE Transactions on Electron Devices

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ER -

In/sub 0.53/Ga/sub 0.47/As MSM photodiodes with transparent CTO Schottky contacts and digital superlattice grading

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