Low-Temperature Direct Growth of Amorphous Boron Nitride Films for High-Performance Nanoelectronic Device Applications

Abstract

We successfully demonstrated the improvement and stabilization of the electrical properties of a graphene field effect transistor by fabricating a sandwiched amorphous boron nitride (a-BN)/graphene (Gr)/a-BN using a directly grown a-BN film. The a-BN film was grown via low-pressure chemical vapor deposition (LPCVD) at a low growth temperature of 250 °C and applied as a protection layer in the sandwiched structure. Both structural and chemical states of the as-grown a-BN were verified by various spectroscopic and microscopic analyses. We analyzed the Raman spectra of Gr/SiO2 and a-BN/Gr/a-BN structures to determine the stability of the device under exposure to ambient air. Following exposure, the intensity of the 2D/G-peak ratio of Gr/SiO2 decreased and the position of the G and 2D peaks red-shifted due to the degradation of graphene. In contrast, the peak position of encapsulated graphene is almost unchanged. We also confirmed that the mobility of a-BN/Gr/a-BN structure is 17,941 cm2/Vs. This synthetic strategy could provide a facile way to synthesize uniform a-BN film for encapsulating various van der Waals materials, which is beneficial for future applications in nanoelectronics.

Tailoring amorphous boron nitride for high-performance two-dimensional electronics

“…Only the 65 °C aBN film exhibits anomalous dielectric performance, with both a low dielectric breakdown strength and high κ value. To date, aBN is reported to exhibit dielectric constants of 1.8–5.5 36 – 39 . The observed changes in dielectric properties may be due to several factors, including material crystallinity, density, and composition.…”

Amorphous BN-Based Synaptic Device with High Performance in Neuromorphic Computing

“…Therefore, when deposited using sputter techniques, it is unavoidable to encounter oxygen in XPS analysis [37,38]. Figure 2a displays the B 1s spectra of a-BN that reveal two peaks related to the B-N (190.5 eV) and B-O (192 eV) bonds [39,40]. This suggests that oxygen participates in the a-BN bonding during the deposition of the metal electrode as well as the dielectric.…”

Suspended 2D Materials: A Short Review

“…Another approach to eliminate the influence of the substrate is to encapsulate 2D materials [45][46][47][48][49]. A notable case is exemplified by the work of Sattari-Esfahlan et al, who fabricated a graphene field-effect transistor (FET) by interposing graphene amid two layers of amorphous boron nitride [46].…”

“…Another approach to eliminate the influence of the substrate is to encapsulate 2D materials [45][46][47][48][49]. A notable case is exemplified by the work of Sattari-Esfahlan et al, who fabricated a graphene field-effect transistor (FET) by interposing graphene amid two layers of amorphous boron nitride [46]. In comparison with conventional graphene FETs, with a mobility within the range of 2000-15,000 cm 2 /Vs, the encapsulated graphene FET demonstrates higher mobility (17,941 cm 2 /Vs).…”