Van der Waals Heterostructure of Hexagonal Boron Nitride with an AlGaN/GaN Epitaxial Wafer for High-Performance Radio Frequency Applications

Abstract

While two-dimensional (2D) hexagonal boron nitride (h-BN) is emerging as an atomically thin and dangling bond-free insulating layer for nextgeneration electronics and optoelectronics, its practical implementation into miniaturized integrated circuits has been significantly limited due to difficulties in large-scale growth directly on epitaxial semiconductor wafers. Herein, the realization of a wafer-scale h-BN van der Waals heterostructure with a 2 in. AlGaN/GaN highelectron mobility transistor (HEMT) wafer using metal−organic chemical vapor deposition is presented. The combination of state-of-the-art microscopic and spectroscopic analyses and theoretical calculations reveals that the heterointerface between ∼2.5 nm-thick h-BN and AlGaN layers is atomically sharp and exhibits a very weak van der Waals interaction without formation of a ternary or quaternary alloy that can induce undesired degradation of device performance. The fabricated AlGaN/GaN HEMT with h-BN shows very promising performance including a cutoff frequency (f T ) and maximum oscillation frequency (f MAX ) as high as 28 and 88 GHz, respectively, enabled by an effective passivation of surface defects on the HEMT wafer to deliver accurate information with minimized power loss. These findings pave the way for practical implementation of 2D materials integrated with conventional microelectronic devices and the realization of future all-2D electronics.

The electronic and interfacial properties of a vdW heterostructure composed of penta-PdSe2and biphenylene monolayers

“…We design the PdSe 2 /BPN heterostructure by vertically stacking the two monolayers. Unlike the heterostructures purely composed of hexagonal building blocks, 15,[52][53][54][55] the PdSe 2 /BPN heterojunction comprises mixed geometric blocks such as tetra-hexa and octagonal blocks of C as well as purely pentagonal blocks composed of Pd and Se atoms. Due to the different lattice symmetries and lattice parameters, special attention is devoted to control the lattice mismatch between the penta-PdSe 2 and BPN layers in order to do calculations using periodic boundary conditions.…”

The interface microstructure and band alignment of hexagonal boron nitride/diamond heterojunctions

“…1f), which are assigned to the transition from B 1s and N 1s core-levels to the π* anti-bonding orbital states of sp 2 -hybridized h-BN, respectively. 32,33 Moreover, the σ* peaks, corresponding to the transitions from the core levels to σ* states, are also observed at ∼199 eV in B K-edge and ∼408 eV in N K-edge. 32,33 The above results indicate that the few-layer h-BN with a smooth surface is indeed directly grown on the CVD diamond substrate.…”

“…32,33 Moreover, the σ* peaks, corresponding to the transitions from the core levels to σ* states, are also observed at ∼199 eV in B K-edge and ∼408 eV in N K-edge. 32,33 The above results indicate that the few-layer h-BN with a smooth surface is indeed directly grown on the CVD diamond substrate.…”

Conformal Growth of Hexagonal Boron Nitride on High-Aspect-Ratio Silicon-Based Nanotrenches

“…The electron count of the excited electrons was 0.75. 46 The broadening parameter was 0.2 eV. Due to the lack of absolute energy reference in the pseudopotential method, an energy alignment scheme was employed to yield comparably meaningful relative energies for structurally and chemically different systems.…”