Damage-induced voltage alteration (DIVA) contrast in SEM images of ion-irradiated semiconductors

Iwona Jóźwik; Adam Barcz; Elżbieta Dąbrowska; Ewa Dumiszewska; Paweł Piotr Michałowski

doi:10.1016/j.ultramic.2019.04.013

Damage-induced voltage alteration (DIVA) contrast in SEM images of ion-irradiated semiconductors

Ultramicroscopy. 2019 Sep:204:6-9. doi: 10.1016/j.ultramic.2019.04.013. Epub 2019 May 8.

Authors

Iwona Jóźwik¹, Adam Barcz², Elżbieta Dąbrowska³, Ewa Dumiszewska³, Paweł Piotr Michałowski³

Affiliations

¹ Łukasiewicz Research Network - Institute of Electronic Materials Technology, 133 Wólczyńska Str., 01-919 Warsaw, Poland; National Centre for Nuclear Research/NOMATEN Centre of Excellence MAB+ Division, 7th A. Soltana Str., Świerk-Otwock, Poland. Electronic address: iwona.jozwik@itme.edu.pl.
² Institute of Electron Technology/Institute of Physics PAS, Al. Lotników 32/46, 02-668 Warsaw, Poland.
³ Łukasiewicz Research Network - Institute of Electronic Materials Technology, 133 Wólczyńska Str., 01-919 Warsaw, Poland.

PMID: 31108365
DOI: 10.1016/j.ultramic.2019.04.013

Abstract

The ion-irradiation damage effects in semiconductors were directly visualized by means of scanning electron microscopy at low beam acceleration voltages (low-kV SEM). The Al_0.55Ga_0.45As (p-type and n-type) epitaxial layers grown over GaAs substrates were irradiated with energetic He⁺ ions with fluencies ranging from 8e12 to 8e13 cm^-2 and studied in cross-sectional view after cleavage. Secondary electron images collected at low energy (0.5 - 1 keV) of primary electrons show strong contrast related to the local differences in the material resistivity resulting from the ion-induced damage. The main aim of the paper is to present, for the first time, the interpretation of the mechanism of SEM image contrast formation, which has been referred to as Damage-Induced Voltage Alteration (DIVA) contrast and is based on the charging effect in SEM. The unrivalled advantage of this imaging technique is the possibility of immediate two-dimensional visualization of damage effects without complex sample preparation.

Keywords: Ion-irradiated damage; Low-ow-kV SEM; Semiconductors.