Variability Modeling for Printed Inorganic Electrolyte-Gated Transistors and Circuits

Electrolyte-gated field-effect transistor technology is an attractive candidate for printed low-power electronics due to its high field-effect mobility and extremely low-voltage operation. Relying on an additive process, inkjet-printed devices display large process variations due to ink-substrate interactions, sensitivity to environmental conditions, such as temperature and humidity, as well as intrinsic variations of the ink. All of these sources of variations may display themselves in non-Gaussian distributions as suggested by our experiments. In this paper, we therefore propose a generic methodology for variability modeling of printed transistors, based on the Gaussian mixture model, which can be used to model any arbitrary distribution of the transistor model parameters. The proposed methodology was tested on two different data sets and has been used to predict the behavior of a measured printed security circuit as well as transistor dc characteristics.