Printable poly(methylsilsesquioxane) dielectric ink and its application in solution processed metal oxide thin-film transistors

Abstract

Thermally cross-linkable poly(methyl silsesquioxane) (PMSQ) has been investigated as a printable dielectric ink to make the gate insulator by aerosol jet printing for solution processed metal oxide (IGZO) thin-film transistors. It was found that with the increase of curing temperatures from 150 to 200 o C the dielectric constant and loss tangent of printed PMSQ layer reduces dramatically. The mobility, leakage 10 current and gate current of PMSQ enabled thin-film transistor reduces accordingly, while the on/off ratio increases with the increase of curing temperature. An interfacial layer is introduced to further improve the on/off ratio to 3×10 5 and reduce the leakage current to 2.6×10 -10 A, which is the best result for solution processed IGZO thin-film transistors using the PMSQ as gate insulator at the curing temperature of only 150 o C. The work has demonstrated the feasibility of fabricating IGZO thin-film transistors by all solution 15 process.

Polymers for 3D Printing and Customized Additive Manufacturing

“…Wu et al employed PMMA/poly(methylsilsesquioxane) nanocomposites as dielectric material for all solution-based thin film transistors. 397 The use of the composite material was motivated by two properties: the material’s outstanding chemical resistance, which facilitates the solution-based layer deposition in subsequent steps such as metallization, and by its curing temperature, which is described as significantly lower than for typical polyimide and polyvinylphenol formulations and enables the modification of flexible polymeric substrates. The latter advantage can be disputed, as Wu and co-workers also illustrated the need for high temperature curing of residual silanol groups or of an additional synthetic step to protect these groups to limit the resulting composites’ leak current density.…”

A review of aerosol jet printing—a non-traditional hybrid process for micro-manufacturing

“…Later optimisation and characterisation showed current ratios of up to 10 6 , off-state drain currents as low as 10 −10 A and threshold voltages of − 0.3 V [5]. Other approaches to develop solution processable, high-capacitance dielectrics have focussed on the development of poly(methylsilsesquioxane) as a gate dielectric in indium-gallium-zinc-oxide transistors [79] or polyfluorinated electrolytes for applications that require higher thermal stability [80].…”

“…TFTs manufactured using AJP were found to differ in performance when compared to equivalent devices manufactured using conventional solution processes, such as spin coating. Wu et al [79] attributed these variances to differences in the electrolyte structure (pin holes), ingress of impurities or residual solvents in the deposit.…”

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

“…A disadvantage, however, is that the processing takes place in a high vacuum system at an elevated temperature. A notable recent achievement by Wu et al 5,6 is the low-temperature solution processing of printable indiumgallium-zinc oxide TFTs at 150 °C. Relatively high mobilities (> 0.8 cm 2 /Vs) were obtained, although an additional passivation layer was required to achieve high on/off ratios and low leakage currents.…”

“…LaZrO X /SiO 2 , PVP/Al 2 O 3 PMMA/SiO 2 , CNO-PMMA, PMSQ are all attractive candidates for solution-processed gate delectrics. [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.…”