Optimization of electron beam induced deposition process for the fabrication of diode-like Pt/SiO2/W devices

Abstract

Pt/SiO2/W devices of controlled size, thickness, and interfaces were fabricated by electron beam induced deposition (EBID) in a focused ion beam (FIB) system, for possible applications as metal-insulator-metal diodes. A systematic study of the deposition parameters used for the fabrication of the devices was carried out by scanning electron microscopy, energy dispersive x-ray spectroscopy, and transmission electron microscopy (TEM). In particular, the morphological and structural quality of the deposited layers, their mutual interfaces, and the thickness of the insulating layer were accurately investigated, being key issues for the application of these multilayer structures as tunneling diodes; to this aim, a novel TEM sample preparation approach was developed, which allows the in situ FIB preparation of ready-to-be-observed multilayer structures; by using this approach, TEM samples can be directly made, by depositing the structures in the same conditions used for the device fabrication, in the correct geometry for the cross sectional investigations and, without any further preparation steps. The capability of the EBID technique to fabricate submicrometer electronic devices with promising electrical properties, such as asymmetry and nonlinearity, was demonstrated.