Memories for the Intelligent Internet of Things

4Thin Film Polymer and Flexible Memories

4.1 Overview

The requirements for processors with embedded memories are very low power and very low cost. For wearable devices, the circuitry must be flexible. Circuits that can be made without the expense of conventional semiconductor processing might lower the cost. For this reason a significant amount of effort has gone into polymer circuits with embedded memories which can be made by inkjet printing or screen printing. Embedded memories that can be made by printing techniques include: ferroelectric, charge trapping, and resistance RAM memories. These efforts produce low performance, but also low power, low cost, and flexible memories. Inkjet printing of large high volume substrates with ferroelectric memory is in production and polymer RRAM and nanocrystal memories are being developed. This technology is important for low cost RFID chips and other circuits without requirements for high performance.

For other IoT applications, such as wearable recreational and medical systems, the performance of polymer circuits is not sufficient. For these applications the performance of silicon chips is required. Technologies are also being developed for integrating systems of silicon chips on flexible substrates. Silicon chips can be transferred to flexible substrates using SOI base wafers to obtain the thin layer of silicon and thin chips can be obtained by using an underlying cavity. Integration of silicon chips on flexible substrates has also ...