Ultrathin Al‐Assisted Al₂O₃ Passivation Layer for High‐Stability Tungsten Diselenide Transistors and Their Ambipolar Inverter

Abstract

2D transition metal dichalcogenides (TMDs) have recently received significant attention owing to their superior electrical, optical, and mechanical properties. However, most previous research on TMDs has not focused on their stability against bias and illumination stress. Here, high‐stability tungsten diselenide (WSe2) field‐effect transistors (FETs) are introduced with an ultrathin Al‐assisted alumina (Al2O3) passivation. Through the Al‐assisted Al2O3 passivation, the transport behavior of the WSe2 FETs is converted from p‐type to ambipolar owing to the n‐type doping effect of Al2O3 passivation. Furthermore, the stability of the WSe2 FETs is highly improved against gate bias and illumination stress owing to the effect of Al2O3 film quality on WSe2 by ultrathin Al predeposition (≈1 nm). To compare the stress effect on the electrical characteristics, three types of devices: 1) pristine WSe2 FETs, 2) WSe2 FET with Al2O3 passivation layer, and 3) WSe2 FETs with Al‐assisted Al2O3 passivation layer, are systematically tested with positive gate bias stress (PBS) and positive gate bias illumination stress (PBIS). Finally, an ambipolar inverter composed of Al‐assisted Al2O3 passivated WSe2 FETs is demonstrated. This study proposes a promising approach that improves the stability of TMD‐based FETs for next‐generation logic applications.

Controlling the Polarity of WSe2 FETs by Interface Engineering for High-Gain CMOS

“…Figure 4c shows the output characteristics of the n-type (black) and ptype (red) devices. The intrinsic doping effect of Al 2 O 3 increases the electronic current of the n-type device on the Al 2 O 3 dielectric layer, 21,22 which can excellently match with the p-type device. Figure 4d presents the electrical properties of the CMOS inverter with different V DD values.…”

Tunable properties and composition of ZnO films supported on metal surfaces

“…Due to their diverse mechanical, thermal, and electronic properties, 1 oxide films are applied in microelectronics, 2 photonics and plasmonics, 3 passivation, 4 biotechnologies, 5 and catalysis. 6 Often thin oxide films are mechanically stabilized by supports, which can change the properties and stability of the films through electronic interactions and induced structural changes.…”

Large-Scale Complementary Logic Circuit Enabled by Al2O3 Passivation-Induced Carrier Polarity Modulation in Tungsten Diselenide

“…Despite the potential of n- and p-channel FETs utilizing WSe 2 , there have been only a few reports on homogeneous CMOS inverters incorporating WSe 2 as the active material. , Nevertheless, these investigations remain restricted and rely solely on thicker or multilayered exfoliated WSe 2 , which have presented insufficient information without any clear technological benefits. Recently an electrostatically doped WSe 2 ambipolar CMOS inverter using an Al-assisted Al 2 O 3 passivation layer has been reported, where the transport characteristics of the WSe 2 FETs were altered from p-type to ambipolar conduction due to the n-doping effect of the Al 2 O 3 passivation. The use of ambipolar transistors in CMOS technology falls short of the current standard, where both n- and p-type transistors are integrated, as the latter offers superior performance and lower power consumption.…”