High‐Performance Top‐Gated Organic Field‐Effect Transistor Memory using Electrets for Monolithic Printed Flexible NAND Flash Memory

Abstract

High‐performance top‐gated organic field‐effect transistor (OFET) memory devices using electrets and their applications to flexible printed organic NAND flash are reported. The OFETs based on an inkjet‐printed p‐type polymer semiconductor with efficiently chargeable dielectric poly(2‐vinylnaphthalene) (PVN) and high‐k blocking gate dielectric poly(vinylidenefluoride‐trifluoroethylene) (P(VDF‐TrFE)) shows excellent non‐volatile memory characteristics. The superior memory characteristics originate mainly from reversible charge trapping and detrapping in the PVN electret layer efficiently in low‐k/high‐k bilayered dielectrics. A strategy is devised for the successful development of monolithically inkjet‐printed flexible organic NAND flash memory through the proper selection of the polymer electrets (PVN or PS), where PVN/‐ and PS/P(VDF‐TrFE) devices are used as non‐volatile memory cells and ground‐ and bit‐line select transistors, respectively. Electrical simulations reveal that the flexible printed organic NAND flash can be possible to program, read, and erase all memory cells in the memory array repeatedly without affecting the non‐selected memory cells.

Non-volatile organic memory with sub-millimetre bending radius

“…In particular, high-performance flexible non-volatile memories based on various data storage principles such as resistive type [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] , flash 4,[25][26][27][28][29] and ferroelectric [30][31][32][33][34][35][36][37][38][39][40] hold great promise in a variety of emerging applications ranging from mobile computing to information management and communication. While the recent advances in this area are impressive, novel organic materials and electronic device structures that can be tightly rolled, crumpled, stretched, sharply folded and unfolded repeatedly without any performance degradation still need to be developed.…”

“…Although significant progress has been made in improving certain characteristics of ferroelectric polymer memories [30][31][32][33][34][35] , only a few works have addressed mechanically flexible Fe-FETs in which characteristic ferroelectric switching has been examined under a relatively mild bending radius on the order of a few millimetres [36][37][38] . Besides ferroelectric memories, most of the previous non-volatile memories are categorized as bendable devices when their bending radii are much greater than 1 mm (Supplementary Table 1).…”

Thin-film organic semiconductor devices: from flexibility to ultraflexibility

“…The active semiconductors can be organic channel materials for OFETs, organic light-emitting materials for OLEDs, organic photoactive materials for OSCs, organic memory materials for OMDs. To date, great improvements have been made for achieving high performance that is comparable to their inorganic counterparts [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18].…”

Strong molecular weight effects of gate-insulating memory polymers in low-voltage organic nonvolatile memory transistors with outstanding retention characteristics

“…18,19 It has been reported that TOMDs have memory functions from ferroelectric polymers, metal nanoparticles or charge trapping layers, and polymer energy well structures. [20][21][22][23][24][25][26][27][28][29][30] However, most TOMDs reported to date have limitations with respect to high operation voltages and/or poor retention (stability) characteristics, even though basic memory functions in transistor structures can be welldemonstrated. Thus, it is very important to achieve both low voltage and high retention characteristics at the same time for further consideration toward commercialization of TOMDs, particularly for mobile applications, of which the first priority is low power consumption, as well as stability.…”