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

Abstract

Thermally cross-linkable poly(methylsilsesquioxane) (PMSQ) has been investigated as a printable dielectric ink to make the gate insulator for solution processed metal oxide (IGZO) thin-film transistors by aerosol jet printing. It was found that by increasing the curing temperature from 150 to 200 °C, the dielectric constant and loss tangent of the printed PMSQ layer reduces dramatically. The mobility, leakage current and gate current of the PMSQ enabled thin-film transistor reduces accordingly, while the on/off ratio increases with the increase of curing temperature. An interfacial layer was introduced to further improve the on/off ratio to 3 × 10⁵ and reduce the leakage current to 2.6 × 10⁻¹⁰ A, which is the best result for the solution processed IGZO thin-film transistors using the PMSQ as the gate insulator at a curing temperature of only 150 °C. The study has demonstrated the feasibility of fabricating IGZO thin-film transistors by an all solution-based process.