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.

Structure, Properties and Applications of Two‐Dimensional Hexagonal Boron Nitride

“…Attempts have been made to lower the temperature using other types of CVD. For example, Liu et al [225] showed catalystfree growth of h-BN on non-metal substrates using plasmaenhanced CVD (PECVD), which consists of two tube furnaces containing ammonia borane and substrate respectively, and a radiofrequency (RF) plasma generator between them. Although energetical plasma could etch materials, nucleation and deposition still dominate during the process owing to h-BN's excellent inertness.…”

Remarkable Reduction of Interfacial Thermal Resistance in Nanophononic Heterostructures

“…besides the material's own thermal conductivity, the interfacial thermal conductance is becoming more and more important with scaling down of the devices, and has continuously attracted intensive research interests. [17][18][19][20][21][22][23][24][25][26] In principle, there always exists contact thermal resistance when phonons transport across the interface between two dissimilar materials. A large number of studies have been done to understand the interfacial thermal conductance of various types of interface, including mass-mismatched solidsolid interface, [27,28] hard-soft materials interface, [29,30] solid-liquid interface, [31] metal-nonmetal interface considering electron-phonon interaction, [32,33] and solid-gas interface.…”

Desolvation‐Triggered Versatile Transfer‐Printing of Pure BN Films with Thermal–Optical Dual Functionality

“…Conventional deposition approaches such as chemical vapor deposition (CVD) [ 16–19 ] require elevated temperatures of 900 °C and are limited to metal substrates requiring additional transfer of the BN film, which often degrades the quality of the film and creates poor interfacial contact. [ 20 ] Advanced growth techniques such as low‐pressure (LP) CVD, [ 21 ] plasma‐enhanced (PE) CVD, [ 22 ] and ion‐beam sputtering deposition (IBSD) [ 23,24 ] that successfully lower the growth temperature to 300 °C and allow direct growth onto dielectric substrates have been proposed. However, these fabrication processes are still limited to the growth substrates and have difficulty in thickness control and mass producibility, which are required for thermal dissipation and light extraction applications, and therefore a new method of fabricating BN films should be developed.…”