The pH-sensing properties of tantalum pentoxide films fabricated by metal organic low pressure chemical vapor deposition

Mikolajick, Thomas; Kühnhold, R; Ryssel, H.

doi:10.1016/s0925-4005(97)00166-4

Cited by 65 publications

(32 citation statements)

References 10 publications

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“…A tantalum oxide layer provides for proton sensitivity (58 mv pH 21 ; ref. 38). High-speed addressing and readout are accomplished by the semiconductor electronics integrated with the sensor array (Fig.…”

Section: A Cmos Integrated Circuit For Sequencingmentioning

confidence: 99%

An integrated semiconductor device enabling non-optical genome sequencing

Rothberg¹,

Hinz²,

Rearick³

et al. 2011

Nature

1,863

1,157

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The seminal importance of DNA sequencing to the life sciences, biotechnology and medicine has driven the search for more scalable and lower-cost solutions. Here we describe a DNA sequencing technology in which scalable, low-cost semiconductor manufacturing techniques are used to make an integrated circuit able to directly perform non-optical DNA sequencing of genomes. Sequence data are obtained by directly sensing the ions produced by template-directed DNA polymerase synthesis using all-natural nucleotides on this massively parallel semiconductor-sensing device or ion chip. The ion chip contains ion-sensitive, field-effect transistor-based sensors in perfect register with 1.2 million wells, which provide confinement and allow parallel, simultaneous detection of independent sequencing reactions. Use of the most widely used technology for constructing integrated circuits, the complementary metal-oxide semiconductor (CMOS) process, allows for low-cost, large-scale production and scaling of the device to higher densities and larger array sizes. We show the performance of the system by sequencing three bacterial genomes, its robustness and scalability by producing ion chips with up to 10 times as many sensors and sequencing a human genome.DNA sequencing and, more recently, massively parallel DNA sequencing 1-4 has had a profound impact on research and medicine. The reductions in cost and time for generating DNA sequence have resulted in a range of new sequencing applications in cancer 5,6 , human genetics 7 , infectious diseases 8 and the study of personal genomes 9-11 , as well as in fields as diverse as ecology 12,13 and the study of ancient DNA 14,15 . Although de novo sequencing costs have dropped substantially, there is a desire to continue to drop the cost of sequencing at an exponential rate consistent with the semiconductor industry's Moore's Law 16 as well as to provide lower cost, faster and more portable devices. This has been operationalized by the desire to reach the $1,000 genome 17 .To date, DNA sequencing has been limited by its requirement for imaging technology, electromagnetic intermediates (either X-rays 18 , or light 19 ) and specialized nucleotides or other reagents 20 . To overcome these limitations and further democratize the practice of sequencing, a paradigm shift based on non-optical sequencing on newly developed integrated circuits was pursued. Owing to its scalability and its low power requirement, CMOS processes are dominant in modern integrated circuit manufacturing 21 . The ubiquitous nature of computers, digital cameras and mobile phones has been made possible by the low-cost production of integrated circuits in CMOS.Leveraging advances in the imaging field-which has produced large, fast arrays for photonic imaging 22 -we sought a suitable electronic sensor for the construction of an integrated circuit to detect the hydrogen ions that would be released by DNA polymerase 23 during sequencing by synthesis, as opposed to a sensor designed for the detection of photons. Although a variety ...

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Section: A Cmos Integrated Circuit For Sequencingmentioning

confidence: 99%

An integrated semiconductor device enabling non-optical genome sequencing

Rothberg¹,

Hinz²,

Rearick³

et al. 2011

Nature

1,863

1,157

View full text Add to dashboard Cite

show abstract

“…In fact, Ta 2 O 5 film is the most promising candidate for conventional dielectric materials for a high electric constant ($20) and low leakage current, 1,2) comparing to the dielectric constant of 3.9 for SiO 2 and 7.5 for Si 3 N 4 . Besides, Ta 2 O 5 films have also been widely applied in catalyst, 3) gas sensors, 4) coating, 5) and piezoelectic materials. 6) However, few studies on the photoluminescence and field emission properties of nanoscale Ta 2 O 5 films have been reported in literatures.…”

Section: Introductionmentioning

confidence: 99%

Optical and Electric Properties of Aligned-Growing Ta<SUB>2</SUB>O<SUB>5</SUB> Nanorods

Wang

Zhu

et al. 2008

Mater. Trans.

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These vertically aligned Ta 2 O 5 nanorods were deposited on Si (100) substrates by thermal deposition in a vacuum of the order of 10 À2 Torr at about 600 C. When excited by 514 nm Ar þ laser, they showed a strong photoluminescence at $622 nm, which was attributed to the oxygen vacancies. In addition, their dielectric constant is $20 in the frequency range from 1 kHz to 10 MHz, far larger than that of SiO 2 and Si 3 N 4 . Due to this cone-shaped morphology, the Ta 2 O 5 nanorods exhibited a threshold field of $8:5 V/mm in field emission and a field enhancement factor of 764 that are sufficiently high for field emission application.

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“…Typical responses are 46 mV/pH [30]. Alternatively, the device may be coated with another dielectric, such as Ta 2 O 5 , which has been shown to give a response as large as 58 mV/pH [21]. The Ta 2 O 5 is a thin insulator and therefore does not modify the cross-talk properties of the individual sensors that have previously been shown to be capable of forming images [16].…”

Section: B Post-processing Of the Cmos Chipmentioning

confidence: 99%

“…The sensitivity varies depending on the exact dielectric used. Several materials have been studied, including SiO 2 , Si 3 N 4 , Al 2 O 3 , SnO 2 , ZrO 2 , and Ta 2 O 5 [17]- [21]. Ta 2 O 5 has proven to be an excellent material with good immunity against interference ions and a wide working pH range [22].…”

Section: Introductionmentioning

confidence: 99%

An Integrated Circuit for Chip-Based Analysis of Enzyme Kinetics and Metabolite Quantification

Cheah

MacDonald

Martin

et al. 2016

IEEE Trans. Biomed. Circuits Syst.

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Abstract-We have created a novel chip-based diagnostic tools based upon quantification of metabolites using enzymes specific for their chemical conversion. Using this device we show for the first time that a solid-state circuit can be used to measure enzyme kinetics and calculate the Michaelis-Menten constant. Substrate concentration dependency of enzyme reaction rates is central to this aim. Ion-sensitive field effect transistors (ISFET) are excellent transducers for biosensing applications that are reliant upon enzyme assays, especially since they can be fabricated using mainstream microelectronics technology to ensure low unit cost, mass-manufacture, scaling to make many sensors and straightforward miniaturisation for use in point-of-care devices. Here, we describe an integrated ISFET array comprising 2 16 sensors. The device was fabricated with a complementary metal oxide semiconductor (CMOS) process. Unlike traditional CMOS ISFET sensors that use the Si 3 N 4 passivation of the foundry for ion detection, the device reported here was processed with a layer of Ta 2 O 5 that increased the detection sensitivity to 45 mV/pH unit at the sensor readout. The drift was reduced to 0.8 mV/hour with a linear pH response between pH 2 -12. A high-speed instrumentation system capable of acquiring nearly 500 fps was developed to stream out the data. The device was then used to measure glucose concentration through the activity of hexokinase in the range of 0.05 mM -231 mM, encompassing glucose's physiological range in blood. Localised and temporal enzyme kinetics of hexokinase was studied in detail. These results present a roadmap towards a viable personal metabolome machine. Index Terms-Biosensor, CMOS, electrochemical sensor, enzyme kinetics, hexokinase, ion-sensitive field effect transistors (ISFET), metabolomics, point-of-care (POC) diagnostics.

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The pH-sensing properties of tantalum pentoxide films fabricated by metal organic low pressure chemical vapor deposition

Cited by 65 publications

References 10 publications

An integrated semiconductor device enabling non-optical genome sequencing

An integrated semiconductor device enabling non-optical genome sequencing

Optical and Electric Properties of Aligned-Growing Ta<SUB>2</SUB>O<SUB>5</SUB> Nanorods

An Integrated Circuit for Chip-Based Analysis of Enzyme Kinetics and Metabolite Quantification

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