Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Printed Thin Film Transistors to be discussed in Tokyo

Abstract:
Printed Thin Film Transistors to be discussed in Tokyo
by Khasha Ghaffarzadeh, Technology Analyst, IDTechEx

A diverse toolkit of electronic components can today be printed. These include batteries, antennas, memories, sensors, etc. An important building block linking all these components is the printed thin film transistor. This vital device enables logic and therefore data processing. Despite years of development however, printed transistors are not yet a commercial reality.

Printed Thin Film Transistors to be discussed in Tokyo

Cambridge, UK | Posted on August 8th, 2012

Far Asia is the primary centre for the development and production of thin film transistors, which are used in display, X-ray detectors, large-area photosensors, etc. Global companies like Samsung and LG are leading the way. This has promoted us to dedicate a session to "Printed Logic" in our Printed Electronics Asia event, www.PrintedElectronicsAsia.com, which takes place October 2-3, 2012 in Tokyo.

In this short article, we will give a brief overall assessment of printed electronics, outlining critical challenges facing printed transistors from both a market and technical prospective. This article will help set the parameters for the debate that we hope to promote in our event.

Where is the value in printing transistors?

Today, we have a rapidly increasing range of material options available for fabricating TFTs, including oxides, organics, etc. In spite of this, amorphous and polycrystalline silicon remain the dominant technologies.

The current fabrication method are all subtractive, regardless of the specifics of the deposition or annealing technique (e.g., plasma enhanced chemical vapour deposition, sputtering, excimer laser annealing, etc). This is because a photolithographic patterning technique can require more than six steps for deposing a single layer. In addition, much of the deposited material is etched away and thus wasted. This adds to both the bill of materials and the processing cost.

In contrast, printing techniques offer an additive fabrication technique. Here, a layer can be directly deposited with as little as three steps. More critically, material wastage will be minimised. These two factors indicate a potential cost saving. It is this strong rationale that underpins the drive towards printed thin film transistors.

Printing thin film transistors offer numerous other advantages too. Primary amongst them are the ability (a) to cover large areas and (b) to print on low-temperature flexible substrates such as paper. Both these attributes can enable a broad range of new markets including ultra large sensor arrays, smart packaging and point-of-sale posters, etc.
www.printedelectronicsworld.com/images/v5/pagesections/420wim/main19559.jpg

What are the challenges?

The technology is at a state where we have a range of printable semiconductor (e.g., the active channel in the transistor) at our disposal. This toolkit includes organics, oxides, CdSe, crushed silicon, liquid silicon, carbon nanotubes, nanowires, etc. None of this semiconductors offer a one-size-fits-all solution and all suffer from significant limitations, including:

Low mobility: field-effect mobility is a key figure-of-merit which determines how fast transistors can switch. Printable semiconductors typically struggle to reach the 0.5-1 cm2/Vs mark. Even reaching this value will not sufficient for many emerging applications, including OLEDs. Indeed, it may not be sufficient to displace the current incumbent technologies, such as amorphous and polycrystalline silicon, which offer 1 and >100 cm2/Vs, respectively.

Low stability: thin film transistors are interfacial devices. A poor interfacial quality (e.g., high density of defect states) will result in unstable devices whose characteristics change during operation. In addition to this, the absence of ultra-high-performance encapsulation can lead to device degradation, particularly when organic semiconductors are involved. This is a major handicap because circuits are designed to tolerate a range of characteristic variations and will cease to function once the device drifts out of the compliance range. Increasing the compliance range will significantly drive the costs up as it often requires incorporating more transistors.

Low spatial uniformity: device characteristics must remain uniform across the device surface in order to maintain a uniform brightness distribution. Therefore, the manufacturing technique must be able to reproduce the same conditions (geometry, contact, interface, etc) over large areas. This is proving to be a major challenge with printing equipment.

Dielectrics: research has been mainly focused on printed semiconductors. This, however, is only a part of the picture. We will also require reliable, pin-hole-free printable dielectrics. This is a challenge, particularly because the annealing and wetting properties of the ink must be compatible with both the under- and over-lying layers. In addition, the printed dielectric must withstand subsequent processing conditions. The outstanding questions over printed dielectrics are likely to mean that printed transistors will initially consist of hybrid structure in which only the semiconductor and the conductors are printed.

Low temperature annealing: flexible substrates tend to have a low annealing temperature. They will constrain the device processing conditions. In turn, this constrain will lead to poor device performance because often high-temperature annealing is a prerequisite for high-quality devices.

In addition to technical challenges, printed thin film transistors are actively searching for markets. In many application areas, the main go-to-market strategy is replacing an existing component/layer in a product. This is a challenge because the incumbent technology is often well-entrenched. Two primary high-volume target markets for printed transistors are:

RFID tags: here the printed versions are envisioned to replace crystalline silicon chips. The challenges however are the HF and UHF communication protocol require the integration of thousands of transistors running at 13.56 MHz and 865-960 MHz, respectively. Given the lack of uniformity, reproducibility and mobility, we assess that displacing silicon will be very difficult. In addition, printed chips will occupy more space. Finally, the RFID business is a pure cost game in which margins are very small (<1 cent) and huge volumes are required for reasonable profits.

Displays: printed thin film transistors may lower the production cost for display backplanes. The challenge here will be lifetime (i.e., change of characteristics during operation) and uniformity. Mobility will also be critical when moving towards OLED and/or 3D display. It is not clear whether printed thin film transistors can meet the technical requirements.

Our assessment is that printed thin film transistors will have to find niche markets in the first instance. These markets are likely to be on low-end disposable products. The printed circuits would require few transistor counts and would only perform simple logic. This approach is likely to require producers to design ready-to-go printed logic platforms which can be incorporated into end products.

The main challenge with this business model is that transistors are complex devices, requiring a large investment and R&D effort to optimise them. Manufactures may therefore be reluctant to invest in the absence of established large target markets.

We invite to attend our Printed Electronics Asia show, www.PrintedElectronicsAsia.com, in Tokyo to join the debate and learn about the latest developments in printed logic.

####

For more information, please click here

Contacts:
Khasha Ghaffarzadeh


Printed Electronics Asia 2012 conference
Event Manager
Mrs. Cara Harrington

Copyright © IDTechEx

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Iranian Researchers Synthesize Stable Ceramic Nanopowders at Room Temperature September 20th, 2014

Arrowhead to Present at BioCentury's NewsMakers in the Biotech Industry Conference September 19th, 2014

SouthWest NanoTechnologies (SWeNT) Receives NIST Small Business Innovation Research (SBIR) Phase 1 Award to Produce Greater than 99% Semiconducting Single-Wall Carbon Nanotubes September 19th, 2014

Toward optical chips: A promising light source for optoelectronic chips can be tuned to different frequencies September 19th, 2014

Flexible Electronics

New research points to graphene as a flexible, low-cost touchscreen solution September 19th, 2014

IEEE International Electron Devices Meeting To Celebrate 60th Anniversary as The Leading Technical Conference for Advanced Semiconductor Devices September 18th, 2014

Excitonic Dark States Shed Light on TMDC Atomic Layers: Berkeley Lab Discovery Holds Promise for Nanoelectronic and Photonic Applications September 11th, 2014

Copper shines as flexible conductor August 29th, 2014

Announcements

Iranian Scientists Separate Zinc Ion at Low Concentrations September 20th, 2014

Arrowhead to Present at BioCentury's NewsMakers in the Biotech Industry Conference September 19th, 2014

SouthWest NanoTechnologies (SWeNT) Receives NIST Small Business Innovation Research (SBIR) Phase 1 Award to Produce Greater than 99% Semiconducting Single-Wall Carbon Nanotubes September 19th, 2014

Toward optical chips: A promising light source for optoelectronic chips can be tuned to different frequencies September 19th, 2014

Events/Classes

Arrowhead to Present at BioCentury's NewsMakers in the Biotech Industry Conference September 19th, 2014

IEEE International Electron Devices Meeting To Celebrate 60th Anniversary as The Leading Technical Conference for Advanced Semiconductor Devices September 18th, 2014

PEN Inc. Chairman, Scott Rickert, Will Webcast a Live Company Update September 25, 1 PM EDT September 17th, 2014

Dolomite to launch Meros TCU-100 temperature controller at Lab-on-a-Chip & Microarray World Congress September 15th, 2014

Printing/Lithography/Inkjet/Inks

RMIT delivers $30m boost to micro and nano-tech August 26th, 2014

SouthWest NanoTechnologies Appoints Matteson-Ridolfi for U.S. Distribution of its SMW™ Specialty Multiwall Carbon Nanotubes August 13th, 2014

An Inkjet-Printed Field-Effect Transistor for Label-Free Biosensing August 11th, 2014

SEMATECH and Newly Merged SUNY CNSE/SUNYIT Launch New Patterning Center to Further Advance Materials Development: Center to Provide Access to Critical Tools that Support Semiconductor Technology Node Development August 7th, 2014

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE