A 10 nm Short Channel MoS₂ Transistor without the Resolution Requirement of Photolithography

Abstract

MoS2 is considered a promising candidate as a channel material for the next generation semiconductor devices owing to its atomic thickness and electrical properties. However, due to the limited resolution of the photolithography, the short channel length MoS2 transistor is still inclusive. In this work, a method to fabricate MoS2 transistors with short channel length is demonstrated, which is realized by the self‐oxidization of aluminum to form an effective isolation between the source and drain electrodes. By this method, 10 nm transistors with 3.65 nm thick multilayer MoS2 are realized. Despite the short channel length, the devices still exhibit a good on/off ratio. Both the transmission electron microscope image and electrical characteristics reveal the realization of 10 nm short channel, and the simulation results also prove it. Throughout aluminum self‐oxidization technology, transistors with 10 nm channel length can be defined by lithography with 100 nm precision. The 2D transistors with self‐oxidized short channel length reduce the threshold of the 10 nm channel's fabrication, and provide new opportunities for scaling down the 2D material‐based transistors.

Ohmic Behavior in Metal Contacts to n/p-Type Transition-Metal Dichalcogenides: Schottky versus Tunneling Barrier Trade-off

“…Moreover, a band gap larger than 1.7 eV and relatively large effective masses mitigate the source-to-drain tunneling. 8,9 However, devices with high performances call for lowresistance ohmic contacts, which are still challenging to obtain. 10−15 Experimental results for metal−TMD contacts typically reported a large Fermi-level pinning (FLP) at the metal−TMD interfaces.…”

Electrode Engineering in MoS2 MOSFET: Different Semiconductor/Metal Interfaces

“…Then, the samples were exposed to the atmosphere for 24 h to oxidize naturally and form AlO x . [11,30] After this step, the MoS 2 was physically transferred onto the ultrathin AlO x (3 nm) which wrapped the Ag electrode (Figure S1c, Supporting Information), where AlO x was used as a tunneling layer to form a direct tunneling current. Figure 1f is the energy band diagram with an ultrathin AlO x tunneling layer.…”

“…Therefore, it is necessary to optimize the contact interface between MoS 2 and metal electrode for improving the performance of MOSFET. Scientific workers have done a large number of research to reduce Rc, [5,[11][12][13][14][15][16][17][18][19][20] where these most effective and representative methods are inserting h-BN tunneling layer and physically transferring metal electrodes. [18,21] But there are still some problems that when previous works transferred metal electrodes to 2D semiconductors, the different metal electrodes have different adhesion to the silicon wafer, making it difficult to strip off the metal electrodes.…”

“…Therefore, the 2D MoS 2 is widely used to research short-channel MOSFET. [9][10][11] In short-channel MOSFET devices, the power consumption is particularly influenced by high contact resistance (R c ) at the metal/semiconductor interfaces. [12,13] In order to reduce the power consumption and increase transmission current, the Ohmic contact is an important factor for 2D MoS 2 MOSFET because it can significantly lower the additional impedance.Compared to the total resistance, the ideal Ohmic R c is relatively small.…”

The Trend of 2D Transistors toward Integrated Circuits: Scaling Down and New Mechanisms

“…[37] MoS 2 transistors at the ultimate scale also demonstrate non-negligible drain-induced barrier-lowering (DIBL) [35] and a degradation in the subthreshold swing (SS). [37,38] This can be attributed to the lack of control over the planar structure in the form of a top gate or a back gate, as shown in Figure 2a,b. A small SS value enables a low operation voltage and a small amount of subthreshold leakage current, and a poor DIBL degrades the voltage gain of the FET.…”