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Integrated sensitive on-chip ion field effect transistors based on wrinkled InGaAs nanomembranes.

Harazim SM, Feng P, Sanchez S, Deneke C, Mei Y, Schmidt OG - Nanoscale Res Lett (2011)

Bottom Line: Self-organized wrinkling of pre-strained nanomembranes into nanochannels is used to fabricate a fully integrated nanofluidic device for the development of ion field effect transistors (IFETs).Constrained by the structure and shape of the membrane, the deterministic wrinkling process leads to a versatile variation of channel types such as straight two-way channels, three-way branched channels, or even four-way intersection channels.The fabrication of straight channels is well controllable and offers the opportunity to integrate multiple IFET devices into a single chip.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany. s.harazim@ifw-dresden.de.

ABSTRACT
Self-organized wrinkling of pre-strained nanomembranes into nanochannels is used to fabricate a fully integrated nanofluidic device for the development of ion field effect transistors (IFETs). Constrained by the structure and shape of the membrane, the deterministic wrinkling process leads to a versatile variation of channel types such as straight two-way channels, three-way branched channels, or even four-way intersection channels. The fabrication of straight channels is well controllable and offers the opportunity to integrate multiple IFET devices into a single chip. Thus, several IFETs are fabricated on a single chip using a III-V semiconductor substrate to control the ion separation and to measure the ion current of a diluted potassium chloride electrolyte solution.

No MeSH data available.


Related in: MedlinePlus

Top view on two IFET devices. (a) Optical microscope images of two devices containing one wrinkled nanochannel each, the electrodes and the microfluidic channels. (b) and (c) are the zoomed images on one device in two different Z-positions focusing on the nanochannel (b) and on the electrodes (c). The unlabeled scale bars are 5 μm.
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Figure 2: Top view on two IFET devices. (a) Optical microscope images of two devices containing one wrinkled nanochannel each, the electrodes and the microfluidic channels. (b) and (c) are the zoomed images on one device in two different Z-positions focusing on the nanochannel (b) and on the electrodes (c). The unlabeled scale bars are 5 μm.

Mentions: After the nanochannel fabrication, the electrical isolation of the entire substrate, including the nanochannel, was carried out by an ALD method by depositing a 15-nm thick Al2O3 layer. The electrodes were then deposited in separate steps starting with the gate electrode on top of the channel. After the gate electrode integration by photolithography processing and electron beam evaporation of 80 nm of gold, a second ALD step isolated the gate electrode completely. The purpose of the second Al2O3 layer is not only to ensure the electrical isolation but also to tune the final inner diameter of the nanochannel. The ALD method allows for a homogenous coating of nanochannels with lengths in the micrometer regime [19]. This coating is of significant importance since ions with a given concentration have a defined Debye length, which needs to be in the same order as the nanochannel dimension [20,21]. The original height of the nanochannel after wrinkling, measured by AFM, was 95 nm. After the first ALD deposition of 15 nm of Al2O3, the inner height had been diminished to 65 nm. By the coating of a 20-nm Al2O3 layer from the second isolation step, the channel height finally reached a total height of 25 nm. After the gate electrode was isolated and the channel size fine-tuned to the desired value, the deposition of the source and drain electrode was also performed by a photolithography and electron beam evaporation step. The source and drain electrodes were separated by 1 μm to that of the nanochannel openings, whereas the gate electrode partially covered the top of the nanochannel (66% of the length). Figure 2 shows optical images of two IFET devices including the electrodes and the microfluidic system. Each nanochannel array shown in Figure 2a provides a large number of wrinkled InGaAs membranes (165 wrinkled membranes per array) which provide various choices of nanochannels to be selected for the IFET fabrication. Almost similar nanochannels of each array were selected to prepare the IFET devices. Figure 2a depicts two arrays of nanochannels containing the processed electrodes and microfluidic structures.


Integrated sensitive on-chip ion field effect transistors based on wrinkled InGaAs nanomembranes.

Harazim SM, Feng P, Sanchez S, Deneke C, Mei Y, Schmidt OG - Nanoscale Res Lett (2011)

Top view on two IFET devices. (a) Optical microscope images of two devices containing one wrinkled nanochannel each, the electrodes and the microfluidic channels. (b) and (c) are the zoomed images on one device in two different Z-positions focusing on the nanochannel (b) and on the electrodes (c). The unlabeled scale bars are 5 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211272&req=5

Figure 2: Top view on two IFET devices. (a) Optical microscope images of two devices containing one wrinkled nanochannel each, the electrodes and the microfluidic channels. (b) and (c) are the zoomed images on one device in two different Z-positions focusing on the nanochannel (b) and on the electrodes (c). The unlabeled scale bars are 5 μm.
Mentions: After the nanochannel fabrication, the electrical isolation of the entire substrate, including the nanochannel, was carried out by an ALD method by depositing a 15-nm thick Al2O3 layer. The electrodes were then deposited in separate steps starting with the gate electrode on top of the channel. After the gate electrode integration by photolithography processing and electron beam evaporation of 80 nm of gold, a second ALD step isolated the gate electrode completely. The purpose of the second Al2O3 layer is not only to ensure the electrical isolation but also to tune the final inner diameter of the nanochannel. The ALD method allows for a homogenous coating of nanochannels with lengths in the micrometer regime [19]. This coating is of significant importance since ions with a given concentration have a defined Debye length, which needs to be in the same order as the nanochannel dimension [20,21]. The original height of the nanochannel after wrinkling, measured by AFM, was 95 nm. After the first ALD deposition of 15 nm of Al2O3, the inner height had been diminished to 65 nm. By the coating of a 20-nm Al2O3 layer from the second isolation step, the channel height finally reached a total height of 25 nm. After the gate electrode was isolated and the channel size fine-tuned to the desired value, the deposition of the source and drain electrode was also performed by a photolithography and electron beam evaporation step. The source and drain electrodes were separated by 1 μm to that of the nanochannel openings, whereas the gate electrode partially covered the top of the nanochannel (66% of the length). Figure 2 shows optical images of two IFET devices including the electrodes and the microfluidic system. Each nanochannel array shown in Figure 2a provides a large number of wrinkled InGaAs membranes (165 wrinkled membranes per array) which provide various choices of nanochannels to be selected for the IFET fabrication. Almost similar nanochannels of each array were selected to prepare the IFET devices. Figure 2a depicts two arrays of nanochannels containing the processed electrodes and microfluidic structures.

Bottom Line: Self-organized wrinkling of pre-strained nanomembranes into nanochannels is used to fabricate a fully integrated nanofluidic device for the development of ion field effect transistors (IFETs).Constrained by the structure and shape of the membrane, the deterministic wrinkling process leads to a versatile variation of channel types such as straight two-way channels, three-way branched channels, or even four-way intersection channels.The fabrication of straight channels is well controllable and offers the opportunity to integrate multiple IFET devices into a single chip.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany. s.harazim@ifw-dresden.de.

ABSTRACT
Self-organized wrinkling of pre-strained nanomembranes into nanochannels is used to fabricate a fully integrated nanofluidic device for the development of ion field effect transistors (IFETs). Constrained by the structure and shape of the membrane, the deterministic wrinkling process leads to a versatile variation of channel types such as straight two-way channels, three-way branched channels, or even four-way intersection channels. The fabrication of straight channels is well controllable and offers the opportunity to integrate multiple IFET devices into a single chip. Thus, several IFETs are fabricated on a single chip using a III-V semiconductor substrate to control the ion separation and to measure the ion current of a diluted potassium chloride electrolyte solution.

No MeSH data available.


Related in: MedlinePlus