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DRUCKMÜLLEROVÁ, Z. KOLÍBAL, M. VYSTAVĚL, T. ŠIKOLA, T.
Original Title
Toward Site-Specific Dopant Contrast in Scanning Electron Microscopy
Type
journal article in Web of Science
Language
English
Original Abstract
Since semiconductor devices are being scaled down to dimensions of several nanometers there is a growing need for techniques capable of quantitative analysis of dopant concentrations at the nanometer scale in all three dimensions. Imaging dopant contrast by scanning electron microscopy (SEM) is a very promising method, but many unresolved issues hinder its routine application for device analysis, especially in cases of buried layers where site-specific sample preparation is challenging. Here, we report on optimization of site-specific sample preparation by the focused Ga ion beam (FIB) technique that provides improved dopant contrast in SEM. Similar to FIB lamella preparation for transmission electron microscopy, a polishing sequence with decreasing ion energy is necessary to minimize the thickness of the electronically dead layer. We have achieved contrast values comparable to the cleaved sample, being able to detect dopant concentrations down to 1x10^16 cm^-3. A theoretical model shows that the electronically dead layer corresponds to an amorphized Si layer formed during ion beam polishing. Our results also demonstrate that contamination issues are significantly suppressed for FIB-treated samples compared with cleaved ones.
Keywords
dopant mapping; scanning electron microscopy (SEM); focused ion beam (FIB); amorphization; semiconductors and semiconductor devices
Authors
DRUCKMÜLLEROVÁ, Z.; KOLÍBAL, M.; VYSTAVĚL, T.; ŠIKOLA, T.
RIV year
2014
Released
20. 5. 2014
ISBN
1431-9276
Periodical
MICROSCOPY AND MICROANALYSIS
Year of study
20
Number
4
State
United States of America
Pages from
1312
Pages to
1317
Pages count
6
BibTex
@article{BUT108633, author="Zdena {Rudolfová} and Miroslav {Kolíbal} and Tomáš {Vystavěl} and Tomáš {Šikola}", title="Toward Site-Specific Dopant Contrast in Scanning Electron Microscopy", journal="MICROSCOPY AND MICROANALYSIS", year="2014", volume="20", number="4", pages="1312--1317", doi="10.1017/S1431927614000968", issn="1431-9276" }