Plastic electronics NFC tag: thin-film transistors on plastic carrier

February 08, 2017 // By Graham Prophet
Describing their work as an innovative tag that is the thinnest and mechanically most robust technology compatible to ISO protocols, at the 2017 International Solid-State Circuits Conference in San Francisco, research centre imec, with Holst Centre and card/board game maker Cartamundi demonstrated a thin-film tag on plastic.

Compatible with the near field communication (NFC) Barcode protocol, a subset of ISO14443-A, which is available as standard in many commercial smartphones, the NFC tag is manufactured in a thin-film transistor technology using indium gallium zinc oxide thin-film transistors (IGZO TFT) on a plastic substrate.

 

Plastic electronics has long been considered as a potential method of implementing relatively low-level functions in a very-low-cost context where silicon might never be viable. Item-level identification, smart food packaging, brand protection and electronic paper are, imec says, just a few examples. Such new applications will require a continuous supply of countless disposable devices. Imec’s IGZO TFT technology uses large-area manufacturing processes that allow for inexpensive production in large quantities - an ideal technology for ubiquitous electronic devices in the Internet-of-Everything.

 

The researchers developed a self-aligned TFT architecture with scaled devices optimized for low parasitic capacitance and high cut-off frequency. This allowed design of a clock division circuit to convert incoming 13.56 MHz carrier frequency into system clock of the plastic chip. Optimizations at logic gate and system level reduced power consumption down to 7.5 mW, enabling readout by commercial smartphones. “These research innovations are the first major achievements of my ERC starting grant”, stated Kris Myny, principal investigator and holder of the prestigious ERC starting grant FLICs (716426),adding, “Making a plastic electronics device compatible to the ISO standard originally designed for silicon CMOS was a very challenging research and development expedition... our collaboration with Cartamundi enabled us to develop a truly industry-relevant solution”.

 

“This innovative hardware solution of plastic NFC tags opens up several new possibilities for NFC deployments,” stated Alexander Mityashin, program manager at imec. “Thanks to the nature of thin-film plastics, the new tags can be made much thinner and they are mechanically very robust. Moreover, the self-aligned IGZO TFT technology offers manufacturing of chips in large volumes and at low cost”.

 

The results were presented in paper