Parallel metal–insulator–metal diode with an ultrathin spin-coated hydrogen silsesquioxane insulating layer

Abstract In this study, we investigated a parallel metal–insulator–metal (MIM) diode with an ultrathin spin-coated hydron silsesquioxane (HSQ) layer. Ti and Au were adopted as the metal electrodes for the large work function difference. Conditions to obtain the ultrathin HSQ layer with a thickness of below 5 nm for tunneling were predicted and Ti/HSQ/Au diode devices with a parallel electrode arrangement were fabricated by using the conditions. The typical current–voltage characteristics of the fabricated diodes exhibited asymmetry of about 1.8 at 3.0 V. It was demonstrated that the dynamic zero bias resistance of the diodes was as low as about 8 MΩ. Based on the Simmons model, the estimated oxide-equivalent thickness of HSQ in the device was about 1.7 nm, which was in good agreement with the prediction. The good figures of merit of the fabricated diodes imply that the spin-coated ultrathin HSQ is very suitable for this application.