“Making a plastic electronics device compatible to the ISO standard originally designed for silicon CMOS was a challenging research and development expedition,” stated Kris Myny, senior researcher at imec.
The NFC tag is manufactured with a thin film transistor technology using indium gallium zinc oxide thin film transistors (IGZO TFT) on a plastic substrate.
“This hardware solution of plastic NFC tags opens up several new possibilities for NFC deployments,” said 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 robust. Moreover, the self-aligned IGZO TFT technology offers manufacturing of chips in large volumes and at low cost.”
The IGZO TFT technology uses large-area manufacturing processes that allow for inexpensive production in large quantities, which makes it suitable for plastic electronics that requires a continuous supply of countless disposable devices.
The researchers developed a self-aligned TFT architecture with scaled devices optimised for low parasitic capacitance and high cut-off frequency. This allowed design of a clock division circuit to convert incoming 13.56MHz carrier frequency into system clock of the plastic chip.
Optimisations at logic gate and system level reduced power consumption down to 7.5mW, enabling readout by commercial smartphones.