Octadecyltrichlorosilane (OTS) deposited films obtained under various conditions. A protocol to produce high-quality OTS films with potential applications in metal-insulator-metal (MIM) diodes.

Abstract

One of the main challenges in the fabrication process of MIM diodes is the ultra-thin thickness and uniformity required in their insulating layer. Currently, there are high-cost processes used to achieve these requirements, but a reliable and low-cost method needs to be developed. Semiconductor’s research has described the use of self-assembling organic molecules in MIM diodes due to their ability to form uniform layers, whose thickness and properties can be tailored depending on the functional groups and carbon chain present in the molecule used. Therefore, in this work, octadecyltrichlorosilane (OTS) films deposited on silicon substrates under different conditions were evaluated to determine which factors promote a high-quality monolayer structure on them to design a protocol to be used during the fabrication of MIM diodes using OTS as a dielectric layer. OTS films were produced following the wet chemical coating method and it was found that maturation time, immersion time and temperature are relevant factors to produce monolayers with potential applications as dielectric material. Furthermore, a protocol is described that indicates a maturation time in OTS solution of 30 min, a reaction (immersion) time of 60 min and an immediate baking step at 90°C for 5 min, conditions that favour the formation of monolayers of 2.4 ± 0.4nm thickness. However, further research is needed to test OTS films as dielectric material and to find correlation between monolayer quality and I-V characteristics of MIM diodes.