Publication detail

Toward Site-Specific Dopant Contrast in Scanning Electron Microscopy

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"
}