Highly conductive nanometer-thick gold films grown on molybdenum disulfide surfaces for interconnect applications

Yu-Wei Zhang,Kuan-Chao Chen,Bo-Yu Wu,Shih-Yen Lin,Chao-Hsin Wu

doi:10.1038/s41598-020-71520-x

Abstract

Thin gold (Au) films (10 nm) are deposited on different substrates by using a e-beam deposition system. Compared with sapphire and SiO2 surfaces, longer migration length of the Au adatoms is observed on MoS2 surfaces, which helps in the formation of a single-crystal Au film on the MoS2 surface at 200 °C. The results have demonstrated that with the assistance of van der Waals epitaxy growth mode, single-crystal 3D metals can be grown on 2D material surfaces. With the improved crystalline quality and less significant Au grain coalescence on MoS2 surfaces, sheet resistance 2.9 Ω/sq is obtained for the thin 10 nm Au film at 100 °C, which is the lowest value reported in literature. The highly conductive thin metal film is advantageous for the application of backend interconnects for the electronic devices with reduced line widths.

Highlights

Thin gold (Au) films (10 nm) are deposited on different substrates by using a e-beam deposition system
The results indicate that with the longer adatom migration length, improved crystalline quality can be obtained for the thin Au film on the MoS2 surface
As discussed in the previous section, the results demonstrate that the longer migration length of Au adatoms on the 2D material surface does help in planar film growth and lower sheet resistance can be obtained on the M oS2 surface

Summary

Introduction

Thin gold (Au) films (10 nm) are deposited on different substrates by using a e-beam deposition system. The results have demonstrated that with the assistance of van der Waals epitaxy growth mode, single-crystal 3D metals can be grown on 2D material surfaces. Besides 2D materials grown on 2D material surfaces, the other issue arises is the possibility of three-dimensional (3D) crystals grown on 2D material surfaces following the same van der Waals epitaxy on the 2D–3D interfaces It has been demonstrated in one previous publication that a thin 3D metal layer can be formed on 2D material surface after post-growth annealing[14]. The same mechanism may lead to a high sticking coefficient of Au adatoms on MoS2 surfaces and form well-stacked Au/MoS2 hetero-structures In this case, the van der Waals epitaxy of Au films with improved crystalline quality could be achieved at relatively low growth temperatures due to the high adatom density on the MoS2 surface. With the improved crystalline quality and less significant Au grain coalescence on M oS2 surfaces, close-to-theory sheet resistance 2.9 Ω/sq can be obtained for the thin 10 nm Au film, which is the lowest value reported in literature

Methods

Results

Conclusion