Towards phase-change contacts in PEALD grown molybdenum disulfide via intercalation by focused-ion beam

Inhalt:
Transition metal dichalcogenides (TMDCs) such as molybdenum disulfide (MoS2) are promising materials for future electronics. However, low resistance contacts to atomic layer deposited MoS2 are not yet well understood since most research is conducted on monocrystalline, chemical vapour deposited MoS2-sheets. Phase transformation to the metallic 1T phase is one of the most promising techniques to reduce contact resistance and has recently been successfully conducted on ALD MoS2 by intercalation in a n-butyllithium solution. This method has significant disadvantages stemming from the contamination potential of alkali metals in clean room facilities and a time-consuming retransformation in the channel region. In this work we present a potential route of lithium intercalation by direct writing via a FIB-SEM System with a novel ion source that drastically reduces contamination risk compared to other processes. We investigate the trans- and retransformation of MoS2 as a function of the chosen dose using optical microscopy, Raman spectroscopy, atomic force microscopy and scanning electron microscopy.