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 (WSe ₂) 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 SiO ₂/Si, quartz, sapphire, silicon or SiO ₂/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 WSe ₂ field-effect transistor are realized with mobility around 56~ 121 cm ² V ⁻¹ s ⁻¹ and saturated power intensity up to 4.23 × 10 ³ 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.

Abstract

Plasma-enhanced chemical vapour deposition (PECVD) is an industrially compatible microelectronics technology. Here, the authors use PECVD to obtain low-temperature, catalyst-free growth of poly-crystalline two-dimensional hexagonal-boron nitride, thus enabling superior thermal dissipation in WSe ₂ field-effect transistors with mobility up to 121 cm ² V ⁻¹ s ⁻¹.