Polymeric gate dielectric interlayer of cross-linkable poly(styrene-r-methylmethacrylate) copolymer for ferroelectric PVDF-TrFE field effect transistor memory

Thin reduced graphene oxide interlayer with a conjugated block copolymer for high performance non-volatile ferroelectric polymer memory

“…The representative ferroelectric polymers include poly(vinylidene fluoride) (PVDF) and its copolymers with trifluoroethylene (TrFE) (PVDF-TrFE) in which ferroelectric switching is accompanied by facile rotation of the bistable permanent dipole between hydrogen and fluorine atoms along the polymer chain upon altering the polarity of an electric field [6]. Since the concept of FeFETs with ferroelectric polymers have been introduced [7,8] significant progresses in memory performance of Fe-FETs have been made by addressing various scientific and technical issues including nondestructive readout capability [5,9,10], scalability, flexibility [11][12][13], printing capability [9,14], endurance [5,15], long data retention [4,5,9], short program pulse width [5], large ON/OFF ratio [4,5,9,10,14] and materials design including electrodes [5], ferroelectric and insulating layers [4,9,16] and semiconducting active channel layers [4,5,9,10,14,[17][18][19][20][21][22][23][24][25].…”

“…Since the charge injection from semiconductor to ferroelectric layer rarely occurred due to the high energy band gap of most ferroelectric polymers in organic Fe-FETs [2], the majority of the previous works have been focused on the interface between metal and PVDF-TrFE for minimizing contamination of a ferroelectric layer by diffusion of metal atoms upon deposition in metal/ferroelectric/metal capacitors [3,26,27] and for developing effective ferroelectric crystal orientation on metal surface modified with self assembled monolayers [28]. In addition, tremendous efforts have been also made for reducing the gate leakage current of a ferroelectric layer which results from many structural defects arising from grain boundaries of semicrystalline polymers, pinholes and residual solvent trapped in the film [17,19]. This issue became more important in particular when designing a low voltage operation FeFET with a very thin ferroelectric insulator.…”

“…A variety of interlayers have been employed, including SiO 2 [21,33], Al 2 O 3 [23,24,34], PVP [4,9,35], and random copolymer of polystyrene and poly(methylmethacrylate) (P(S-r-MMA)) [17] with the general design rule that makes an uniform interlayer as thin as possible while keeping high capacitance. Additional benefits of polymeric interlayers such as cost effective fabrication based on solution processes and interfacial compatibility with ferroelectric polymer have made them very attractive for the purpose.…”

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).…”