Chemical vapor deposition of hexagonal boron nitride on metal-coated wafers and transfer-free fabrication of resistive switching devices

Abstract

Due to their outstanding electronic and physical properties, two-dimensional (2D) materials have attracted much interest for the fabrication of solid-state microelectronic devices. Among all methods to synthesize 2D materials, chemical vapor deposition (CVD) is the most attractive in the field of solid-state microelectronics because it can produce high quality 2D material in a scalable manner. However, the high temperatures (>900 °C) required during the CVD growth of the 2D materials impede their direct synthesis on metal-coated wafers due to prohibitive metal diffusion and de-wetting. This makes necessary carrying out the 2D materials CVD growth independently on metallic foils, and transfer them on the wafers using polymer scaffolds. However, this process is slower, more expensive, and can lead to abundant contamination and cracks in the 2D material. Here we present a facile method to allow the direct growth of multilayer hexagonal boron nitride (h-BN) on Ni-coated Si wafers, which consists on placing a protective cover 30 μm above the Ni surface. The resulting h-BN stacks have been used to fabricate Au/Ti/h-BN/Ni memristors with low cycle-to-cycle variability. This work contributes to the integration of 2D materials in solid-state micro- and nano-electronic technologies.