Roll-to-roll printed resistive WORM memory on a flexible substrate

Abstract

The fabrication process and the operation characteristics of a fully roll-to-roll printed resistive write-once-read-many memory on a flexible substrate are presented. The low-voltage (<10 V) write operation of the memories from a high resistivity '0' state to a low resistivity '1' state is based on the rapid electrical sintering of bits containing silver nanoparticles. The bit ink is formulated by mixing two commercially available silver nanoparticle inks in order to tune the initial square resistance of the bits and to create a self-organized network of percolating paths. The electrical performance of the memories, including read and write characteristics, is described and the long-term stability of the less stable '0' state is studied in different environmental conditions. The memories can find use in low-cost mass printing applications.

Progress of alternative sintering approaches of inkjet-printed metal inks and their application for manufacturing of flexible electronic devices

“…119 An AC eld was applied by mobile electrodes, which were situated slightly above the sample (Fig. [122][123][124][125] Andersson et al described the fabrication of these devices on photopaper based on the printing of a Ag NP ink, which has an initially high resistance. The electrical eld is able to overcome the electrode gap, couple into the printed Ag NP ink and cause local sintering.…”

“…The electrical eld is able to overcome the electrode gap, couple into the printed Ag NP ink and cause local sintering. 125 Electrical sintering demonstrates a fast and selective sintering approach that has been used to sinter Ag NP inks on various substrates such as glass, PI, PET and paper obtaining conductance values of up to 50% of bulk Ag without damaging the substrate material. The counter electrode can either be situated below the substrate or be operated as a second electrode above the substrate.…”

Inkjet-Printed Multi-Bit Low-Voltage Fuse-Type Write-Once-Read-Many Memory Cell

“…Compared to the popularly studied re-programmable non-volatile memories [7][8][9][10], write-once read-many (WORM) memories are more suitable for those envisioned applications, since they only require programming once, and very stable memory states can be formed. Electrically programmed WORM based on fuses or anti-fuses have been investigated, and can be realized in either a one-layer horizontal structure or a multi-layer vertical structure [11][12][13][14][15][16][17]. The horizontal structure of one layer is more suited for mass production with high yield using existing printing techniques, and the electro-thermal behavior is also more robust and predictable [13].…”

“…Therefore, two-state WORM memories can be formed between the unwritten high-resistance "0" state and the written low-resistance "1" state. Although this type of anti-fuse WORM has advantages of low writing power and energy, its un-written state can be strongly influenced by the storage temperature and relative humidity [13][14][15]. The other WORM type is represented by fuses, with which, the unwritten "0" state is of low-resistance, and after electrical fusing, the pre-fabricated resistor tracks are physically broken to obtain the written "1" state of high resistance [16], [17].…”

Printed low-voltage programmable write-once-read-many-memories

“…applying a low-voltage (< 6 V) pulse over an un-sintered nanoparticle structure [4]. Fabrication of these anti-fuse type WORM memories can be made both with inkjet (to allow design freedom and easy integration) [4] and with high-throughput roll-to-roll (R2R) printing methods (to reach higher volumes) [5]. The stability of the less stable "0" state has been found to be dependent on the environmental conditions, such as humidity, and device encapsulation is therefore required.…”