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

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 degrees 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 x 10(5) and reduce the leakage current to 2.6 x 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 degrees C. The study has demonstrated the feasibility of fabricating IGZO thin-film transistors by an all solution-based process.