Integrated circuits based on two-dimensional semiconductors require ultrathin gate insulators that can provide high interface quality and dielectric reliability, minimized electrically active traps and efficient gate controllability. However, existing two-dimensional insulators do not provide a good trade-off in terms of bandgap, breakdown strength, dielectric constant, leakage current and bias temperature stability. Here, we show that single crystals of magnesium niobate (MgNb₂O₆) can be obtained through a buffer-controlled epitaxial growth process on a mica substrate. The atomically thin MgNb₂O₆ crystals have a wide bandgap (around 5.0 eV), high dielectric constant (around 20), large breakdown voltage (around 16 MV cm⁻¹) and good thermal reliability. The MgNb₂O₆ can form a van der Waals interface with monolayer molybdenum disulfide (MoS₂) with an extremely low density of trap states. MoS₂ field-effect transistors with MgNb₂O₆ gate dielectrics exhibit a hysteresis under 0.9 mV (MV cm⁻¹)⁻¹, a subthreshold swing of 62 mV dec⁻¹, an on/off current ratio of up to 4 × 10⁷ and high electrical reliability at 500 K. The excellent electrostatic controllability of MgNb₂O₆ allowed us to create graphene-contacted transistors and inverter circuits with a channel length of 50 nm.

基于二维半导体的集成电路需要超薄栅极绝缘体，以提供高界面质量和介电可靠性、最小化的电活性陷阱和高效的栅极可控性。然而，现有的二维绝缘体在带隙、击穿强度、介电常数、漏电流和偏置温度稳定性方面没有提供良好的权衡。在这里，我们表明可以通过云母基板上的缓冲液控制外延生长工艺获得铌酸镁（MgNb ₂ O ₆ ）单晶。原子级薄的MgNb ₂ O ₆晶体具有宽带隙（约5.0 eV）、高介电常数（约20）、大击穿电压（约16 MV cm ^-1 ）和良好的热可靠性。 MgNb ₂ O ₆可以与单层二硫化钼（MoS ₂ ）形成陷阱态密度极低的范德华界面。采用 MgNb ₂ O ₆栅极电介质的 MoS ₂场效应晶体管表现出低于 0.9 mV (MV cm ^{− 1} ) ^{− 1 的}磁滞、62 mV dec ⁻¹的亚阈值摆幅、高达 4 × 10 的开/关电流比⁷和 500 K 下的高电气可靠性。MgNb ₂ O ₆优异的静电可控性使我们能够创建沟道长度为 50 nm 的石墨烯接触晶体管和逆变器电路。