Conformal hexagonal-boron nitride dielectric interface for tungsten diselenide devices with improved mobility and thermal dissipation.

ABSTRACT

Relatively low mobility and thermal conductance create challenges for application of tungsten diselenide (WSe2) in high performance devices. Dielectric interface is of extremely importance for improving carrier transport and heat spreading in a semiconductor device. Here, by near-equilibrium plasma-enhanced chemical vapour deposition, we realize catalyst-free growth of poly-crystalline two-dimensional hexagonal-boron nitride (2D-BN) with domains around 20~ 200 nm directly on SiO2/Si, quartz, sapphire, silicon or SiO2/Si with three-dimensional patterns at 300 °C. Owing to the atomically-clean van-der-Walls conformal interface and the fact that 2D-BN can better bridge the vibrational spectrum across the interface and protect interfacial heat conduction against substrate roughness, both improved performance and thermal dissipation of WSe2 field-effect transistor are realized with mobility around 56~ 121 cm2 V-1 s-1 and saturated power intensity up to 4.23 × 103 W cm-2. Owing to its simplicity, conformal growth on three-dimensional surface, compatibility with microelectronic process, it has potential for application in future two-dimensional electronics.