Ultralow Schottky Barrier Height Achieved by Using Molybdenum Disulfide/Dielectric Stack for Source/Drain Contact

Abstract

Energy barrier formed at a metal/semiconductor interface is a critical factor determining the performance of nanoelectronic devices. Although diverse methods for reducing the Schottky barrier height (SBH) via interface engineering have been developed, it is still difficult to achieve both an ultralow SBH and a low dependence on the contact metals. In this study, a novel structure, namely, a metal/transition-metal dichalcogenide (TMD) interlayer (IL)/dielectric IL/semiconductor (MTDS) structure, was developed to overcome these issues. Molybdenum disulfide (MoS2) is a promising TMD IL material owing to its interface characteristics, which yields a low SBH and reduces the reliance on contact metals. Moreover, an ultralow SBH is achieved via the insertion of an ultrathin ZnO layer between MoS2 and a semiconductor, thereby inducing an n-type doping effect on the MoS2 IL and forming an interface dipole in the favorable direction at the ZnO IL/semiconductor interfaces. Consequently, the lowest SBH (0.07 eV) and a remarkable improvement in the reverse current density (by a factor of approximately 5400) are achieved, with a wide room for contact-metal dependence. This study experimentally and theoretically validates the effect of the proposed MTDS structure, which can be a key technique for next-generation nanoelectronics.

Edge‐Assisted Epitaxy of 2D TaSe2‐MoSe2 Metal–Semiconductor Heterostructures and Application to Schottky Diodes

“…[23][24][25][26][27] Therefore, to fabricate high-performance 2D electronic devices and investigate the intrinsic properties of the 2D semiconductors, achieving Schottky contact-type between 2D metals and 2D semiconductors is of great significance. [28][29][30][31][32][33][34] According to the reported literatures, a few strategies including using graphene or 2D metallic (TMDs) materials as electrodes, [35][36][37][38] phase engineering of 2D semiconductors to construct planar metal-semiconductor heterostructures, [39,40] and thermal evaporation of low melting point metals to create Van der Waals (vdWs) contacts, [29,41] have been adopted to improve the electrical contacts to 2D semiconductor devices. However, the approach with artificial exfoliation and stacking of graphene or 2D metals onto 2D semiconductors in the vertical direction is still far from satisfactory, because of the low yield and impurity-involved transfer process.…”

Barrier reduction and current transport mechanism in Pt/n-InP Schottky diodes using atomic layer deposited ZnO interlayer

“…Because of these reasons, ALD grown ZnO has been used for various devices such as transparent electrode [6,8], active medium for fiber-optic Fabry-Perot interferometer [9], photocatalysis [12], electron transporting layers in organic solar cells [13], and thin film transistor circuits [14]. Most of all, ALD grown ZnO has been employed to modify the interface characteristics in metal/semiconductor (MS) contacts [15,16].…”

“…About 1.5 nm thick ZnO was also found to act as an effective passivation layer for HfO 2 films on InP substrate [24]. Due to the high electron affinity of ZnO [15], ZnO/semiconductor can provide negative conduction band offset. Recently, Algadi et al employed a 10 nm thick ZnO IL in indium tin oxide (ITO)/InP Schottky photodetectors and they attributed the improved efficiency to the hole barrier by the valence band offset at the ZnO/InP interface [25].…”