Direct photopatternable organic–inorganic hybrid gate dielectric for solution-processed flexible ZnO thin film transistors

Abstract

A direct photopatternable organosiloxane-based organic-inorganic hybrid gate dielectric was synthesized. The sol-gel derived hybrid dielectric could be cured at a temperature sufficiently low enough to apply to temperature-sensitive polymeric substrates, whilst maintaining good electrical properties. The addition of hexa(methoxymethyl)melamine minimizes the polar silanol group by enhancing the cross-linking reaction and improves the film density, so that the resulting hybrid dielectric retains both thermal and chemical stability against the highly basic aqueous semiconductor precursor, forming a coherent interface between the dielectric and the semiconductor. The synthesized hybrid materials allow for a high-performance solution-processed flexible ZnO transistor on polymeric substrate at 150 C.

Optimization of a Solution-Processed SiO2 Gate Insulator by Plasma Treatment for Zinc Oxide Thin Film Transistors

“…7.5 x 10 -7 A/cm 2 at 1 MV/cm, which is 13 comparable to the conductivity of this insulator reported by others. [3][4]29 For this sample, the hysteresis in the J vs E characteristic is significantly reduced. As the plasma treatment power was increased to 80 W, a similar current density to that exhibited for 40 W OCAPS is noted ( Fig.…”

“…[3][4][5][6] For example, ZnO TFTs using spin coated alumina/polyimide 7 cured at 200 °C and HfLaO X 5 cured at 500 °C have been reported (mobilities of 0.1 cm 2 /Vs and 1.6 cm 2 /Vs, respectively). In other work, either the processing temperature was too high for flexible substrates or the devices exhibited poor electrical properties.…”

Solution-processed SiO2 gate insulator formed at low temperature for zinc oxide thin-film transistors

“…7 Although both ZnO and the gate insulator were formed by spin coating and a relatively low annealing temperature of 230 °C was employed, the devices possessed a field effect mobility of 0.32 cm 2 /Vs, a threshold voltage of 0.89 V and on/off ratio of ~ 10 5 . Silicon dioxide (SiO 2 ), deposited by plasma-enhanced CVD, has been extensively used as a gate insulator for ZnO TFTs as the devices generally show excellent electrical performance, with high mobility, on/off ratio and stability.…”

“…[1][2][3][4][5][6] However, it should be noted that there are relatively few studies reporting ZnO TFTs using solution processing for fabricating both the semiconductor and gate insulator layers. [7][8][9][10] There remain many issues to be addressed. For example, Jung et al 7 noted that films of organic gate insulators including poly(4-vinyphenol), polymethacrylate, polyimide and polyvinyl alcohol can be solution processed at low temperature.…”

“…[7][8][9][10] There remain many issues to be addressed. For example, Jung et al 7 noted that films of organic gate insulators including poly(4-vinyphenol), polymethacrylate, polyimide and polyvinyl alcohol can be solution processed at low temperature. However, the thin films can easily be damaged by ammonia in the ZnO solution.…”