Polarity-controllable MoS₂ transistor for adjustable complementary logic inverter applications

Abstract

A MoS2-based field effect transistor has been exhibited with the selective operation of either p- or n-type characteristics in the same device. Compared to existing individual devices, our device could save almost twice the process time and price.

Engineering Top Gate Stack for Wafer-Scale Integrated Circuit Fabrication Based on Two-Dimensional Semiconductors

“…It is worth noting that once the Al interlayer in the MoS 2 -FET (Al/Au bi-layer gate stack) is fully oxidized, the electrical performance of the device becomes stable. Also, the system’s energy band structure depends on the number of electric dipoles, ,, which is determined by the Al interlayer’s thickness.…”

“…The MoS 2 -FET with the Al 2 O 3 /Au TG stack, in which the Al 2 O 3 dielectric layer (1.5 nm) is grown by the Al 2 O 3 target, shows a much more enhanced mode than the MoS 2 -FET with the Al/Au bi-layer gate stack, though with similar dielectric layer thickness. Therefore, unlike the pristine HfO 2 layer with fewer positive charges, , for a MoS 2 -FET with an Al/Au bi-layer gate stack, positive surplus charges generate in the dielectric layer due to the additional Vo created by the oxidation–reduction reactions, and thus the dipole is induced by the relevant charge transfer. , …”

“…Numerous two-dimensional (2D) semiconductors have been considered promising materials for next-generation electronic devices, particularly advanced field-effect transistors (FETs) to extend Moore’s law. − The 2D transition-metal dichalcogenides (TMDs), such as an extensively investigated molybdenum disulfide (MoS 2 ), can perfectly satisfy most requirements for building high-performance FETs. − Recently, the research trend of 2D semiconductors has switched from the single FET fabrication to the fabrication of fundamental logic blocks and integrated multistage circuits, aiming to construct integrated circuits (ICs) and low-power consumption circuits. − Logic circuits with simple logical functions have already been demonstrated based on both exfoliated MoS 2 sheets ,,− and large-area MoS 2 films synthesized by chemical vapor deposition (CVD). ,, However, their practical applications in cascaded logic stages, which are essential for large-scale ICs, − have remained a challenge due to difficulties in achieving accurate control of the logic level state and satisfying device uniformity.…”

“…However, this is unsuitable for 2D-TMDs due to the introduction of severe lattice damage in its crystal structure. − Changing the work function of the metal gate is another efficient way to control V TH . , For instance, Al and Pt gates with different work functions enable either accumulation or depletion state of 2D-TMD channels . Nevertheless, similar to the gate size modulation, this method can work only in a limited range with discrete work function values. , A more feasible method of V TH modulation is to control the interfacial states of the dielectric layer on top of the 2D-TMD channel. , However, it is difficult to control the properties of the complex dielectric layer precisely due to the weak interface and unstable growth process. − …”

“…35,36 A more feasible method of V TH modulation is to control the interfacial states of the dielectric layer on top of the 2D-TMD channel. 22,37 However, it is difficult to control the properties of the complex dielectric layer precisely due to the weak interface and unstable growth process. 38−40 In this work, based on the wafer-scale MoS 2 continuous films, a non-destructive doping strategy is developed to individually control the V TH of MoS 2 top-gated FETs.…”