Nanostructured electrodes for biocompatible CMOS integrated circuits

Anthony H D Graham, Christopher R Bowen, J Robbins, G Lalev, Frank Marken, John Taylor

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

This paper reports on the adaptation of standard complementary metal oxide semiconductor (CMOS) integrated circuit (IC) technology for biocompatibility, enabling a low-cost solution for drug discovery pharmacology, neural interface systems, cell-based biosensors and electrophysiology. The basis for the process is the anodisation of IC aluminium electrodes to form nanoporous alumina. The porous alumina was electrochemically thinned to reduce the alumina electrode impedance. For applications where a porous electrode surface is either preferred or acceptable, we demonstrated that porosity can be manipulated at room temperature by modifying the anodising electrolyte to include up to 40% polyethylene glycol and reducing the phosphoric acid concentration from 4% (w/v) to 1%. For applications requiring a planar microelectrode surface, a noble metal was electrodeposited into the pores of the alumina film. Limited success was achieved with a pH 7 platinum and pH 5 gold cyanide bath but good results were demonstrated with a pH 0.5 gold chloride bath which produced planar biocompatible electrodes. A further reduction in impedance was produced by deposition of platinum-black, which may be a necessary additional step for demanding applications such as neuronal recording. During this work a capability for real-time electrochemical impedance spectroscopy (EIS) was developed to study anodisation, barrier oxide thinning, oxide breakdown and electrodeposition processes. To study the pore morphology, focused ion beam (FIB) was employed to produce cross-sectional cuts of the IC features which were inspected by SEM with an 'In-lens' detector. The anodisation process and the optional electrodeposition steps require only simple bench equipment operated at room temperature and is therefore a viable route for manufacturing low-cost biocompatible electrodes from standard CMOS ICs.
Original languageEnglish
Pages (from-to)697-706
Number of pages10
JournalSensors and Actuators B-Chemical
Volume147
Issue number2
DOIs
Publication statusPublished - 3 Jun 2010

Fingerprint

CMOS integrated circuits
Aluminum Oxide
integrated circuits
CMOS
Alumina
aluminum oxides
Electrodes
electrodes
gold cyanide
impedance
Platinum
porosity
Electrodeposition
electrodeposition
Oxides
Integrated circuits
baths
platinum black
Gold
electrophysiology

Keywords

  • electrode
  • anodic aluminum oxide (AAO)
  • CMOS
  • biosensor
  • impedance
  • biocompatibility

Cite this

Nanostructured electrodes for biocompatible CMOS integrated circuits. / Graham, Anthony H D; Bowen, Christopher R; Robbins, J; Lalev, G; Marken, Frank; Taylor, John.

In: Sensors and Actuators B-Chemical, Vol. 147, No. 2, 03.06.2010, p. 697-706.

Research output: Contribution to journalArticle

@article{7b333d019a0f4d238d46728d0cc3ba2e,
title = "Nanostructured electrodes for biocompatible CMOS integrated circuits",
abstract = "This paper reports on the adaptation of standard complementary metal oxide semiconductor (CMOS) integrated circuit (IC) technology for biocompatibility, enabling a low-cost solution for drug discovery pharmacology, neural interface systems, cell-based biosensors and electrophysiology. The basis for the process is the anodisation of IC aluminium electrodes to form nanoporous alumina. The porous alumina was electrochemically thinned to reduce the alumina electrode impedance. For applications where a porous electrode surface is either preferred or acceptable, we demonstrated that porosity can be manipulated at room temperature by modifying the anodising electrolyte to include up to 40{\%} polyethylene glycol and reducing the phosphoric acid concentration from 4{\%} (w/v) to 1{\%}. For applications requiring a planar microelectrode surface, a noble metal was electrodeposited into the pores of the alumina film. Limited success was achieved with a pH 7 platinum and pH 5 gold cyanide bath but good results were demonstrated with a pH 0.5 gold chloride bath which produced planar biocompatible electrodes. A further reduction in impedance was produced by deposition of platinum-black, which may be a necessary additional step for demanding applications such as neuronal recording. During this work a capability for real-time electrochemical impedance spectroscopy (EIS) was developed to study anodisation, barrier oxide thinning, oxide breakdown and electrodeposition processes. To study the pore morphology, focused ion beam (FIB) was employed to produce cross-sectional cuts of the IC features which were inspected by SEM with an 'In-lens' detector. The anodisation process and the optional electrodeposition steps require only simple bench equipment operated at room temperature and is therefore a viable route for manufacturing low-cost biocompatible electrodes from standard CMOS ICs.",
keywords = "electrode, anodic aluminum oxide (AAO), CMOS, biosensor, impedance, biocompatibility",
author = "Graham, {Anthony H D} and Bowen, {Christopher R} and J Robbins and G Lalev and Frank Marken and John Taylor",
year = "2010",
month = "6",
day = "3",
doi = "10.1016/j.snb.2010.03.030",
language = "English",
volume = "147",
pages = "697--706",
journal = "Sensors and Actuators B: Chemical",
issn = "0925-4005",
publisher = "Elsevier",
number = "2",

}

TY - JOUR

T1 - Nanostructured electrodes for biocompatible CMOS integrated circuits

AU - Graham, Anthony H D

AU - Bowen, Christopher R

AU - Robbins, J

AU - Lalev, G

AU - Marken, Frank

AU - Taylor, John

PY - 2010/6/3

Y1 - 2010/6/3

N2 - This paper reports on the adaptation of standard complementary metal oxide semiconductor (CMOS) integrated circuit (IC) technology for biocompatibility, enabling a low-cost solution for drug discovery pharmacology, neural interface systems, cell-based biosensors and electrophysiology. The basis for the process is the anodisation of IC aluminium electrodes to form nanoporous alumina. The porous alumina was electrochemically thinned to reduce the alumina electrode impedance. For applications where a porous electrode surface is either preferred or acceptable, we demonstrated that porosity can be manipulated at room temperature by modifying the anodising electrolyte to include up to 40% polyethylene glycol and reducing the phosphoric acid concentration from 4% (w/v) to 1%. For applications requiring a planar microelectrode surface, a noble metal was electrodeposited into the pores of the alumina film. Limited success was achieved with a pH 7 platinum and pH 5 gold cyanide bath but good results were demonstrated with a pH 0.5 gold chloride bath which produced planar biocompatible electrodes. A further reduction in impedance was produced by deposition of platinum-black, which may be a necessary additional step for demanding applications such as neuronal recording. During this work a capability for real-time electrochemical impedance spectroscopy (EIS) was developed to study anodisation, barrier oxide thinning, oxide breakdown and electrodeposition processes. To study the pore morphology, focused ion beam (FIB) was employed to produce cross-sectional cuts of the IC features which were inspected by SEM with an 'In-lens' detector. The anodisation process and the optional electrodeposition steps require only simple bench equipment operated at room temperature and is therefore a viable route for manufacturing low-cost biocompatible electrodes from standard CMOS ICs.

AB - This paper reports on the adaptation of standard complementary metal oxide semiconductor (CMOS) integrated circuit (IC) technology for biocompatibility, enabling a low-cost solution for drug discovery pharmacology, neural interface systems, cell-based biosensors and electrophysiology. The basis for the process is the anodisation of IC aluminium electrodes to form nanoporous alumina. The porous alumina was electrochemically thinned to reduce the alumina electrode impedance. For applications where a porous electrode surface is either preferred or acceptable, we demonstrated that porosity can be manipulated at room temperature by modifying the anodising electrolyte to include up to 40% polyethylene glycol and reducing the phosphoric acid concentration from 4% (w/v) to 1%. For applications requiring a planar microelectrode surface, a noble metal was electrodeposited into the pores of the alumina film. Limited success was achieved with a pH 7 platinum and pH 5 gold cyanide bath but good results were demonstrated with a pH 0.5 gold chloride bath which produced planar biocompatible electrodes. A further reduction in impedance was produced by deposition of platinum-black, which may be a necessary additional step for demanding applications such as neuronal recording. During this work a capability for real-time electrochemical impedance spectroscopy (EIS) was developed to study anodisation, barrier oxide thinning, oxide breakdown and electrodeposition processes. To study the pore morphology, focused ion beam (FIB) was employed to produce cross-sectional cuts of the IC features which were inspected by SEM with an 'In-lens' detector. The anodisation process and the optional electrodeposition steps require only simple bench equipment operated at room temperature and is therefore a viable route for manufacturing low-cost biocompatible electrodes from standard CMOS ICs.

KW - electrode

KW - anodic aluminum oxide (AAO)

KW - CMOS

KW - biosensor

KW - impedance

KW - biocompatibility

UR - http://www.scopus.com/inward/record.url?scp=77953323650&partnerID=8YFLogxK

UR - http://dx.doi.org/10.1016/j.snb.2010.03.030

U2 - 10.1016/j.snb.2010.03.030

DO - 10.1016/j.snb.2010.03.030

M3 - Article

VL - 147

SP - 697

EP - 706

JO - Sensors and Actuators B: Chemical

JF - Sensors and Actuators B: Chemical

SN - 0925-4005

IS - 2

ER -