Facile controlled growth of multilayer h-BN thin films using spaced-confined APCVD and its gate dielectric application

Abstract

Due to its excellent insulativity, thermal conductivity, chemical inertness and ultraflat surface, multilayer hexagonal boron nitride (h-BN) has become a favorable dielectric for two-dimensional materials or other conventional semiconductors. Multilayer h-BN can also serve as a functional material in deep ultraviolet optoelectronic or novel memory devices. However, the utilization of h-BN in electronic and optoelectronic implementations has been severely impeded by the challenge of preparing large-area multilayer thin films. In this work, we achieved the controlled synthesis of centimeter-scale multilayer h-BN using a space confined route within an atmospheric pressure chemical vapor deposition (APCVD) system. Using thorough material characterizations, the uniformity of multilayer h-BN is identified. We find that the thickness of multilayer h-BN can be fine-tuned with APCVD parameters and the growth mechanism in the confined space is systematically scrutinized. The multilayer h-BN thin film is further used as the gate dielectric for a hydrogen-terminated diamond field effect transistor (FET), which exhibits comparable performance with the devices with common dielectrics. Our work provides a novel strategy for the large-scale synthesis of multilayer h-BN thin films, paving the way for realizing its full potentials in a panoply of applications.