Implantation and activation of high concentrations of boron in germanium

Document Type

Article

Publication Date

11-1-2005

Abstract

There is renewed interest in the development of Ge-based devices. Implantation and dopant activation are critical process steps for future Ge devices fabrication. Boron is a common p-type dopant, which remarkably is active immediately after implantation in Ge at low doses. This paper examines the effect of increasing dose (i.e., 5 × 1013 - 5 × 1016 cm-2) and subsequent annealing (400 °C-800 °C for 3 h in nitrogen) on activation and diffusion of boron in Ge. Secondary ion mass spectrometry (SIMS), spreading resistance profiling (SRP), high resolution X-ray diffraction (HRXRD), Rutherford backscattering spectrometry (RBS), and nuclear reaction analysis (NRA) are used to characterize the implants before and after annealing. It is found that very high fractions of the boron dose (∼5%-55%) can be incorporated substitutionally immediately after implantation leading to very high hole concentrations, ≥ 2 × 1020 cm-3, deduced from SRP. Small increases in activation after annealing are observed, however, 100% activation is not indicated by either SRP or NRA. Negligible diffusion after annealing at either 400 °C or 600 °C for 3 h was, furthermore, observed. © 2005 IEEE.

Identifier

27744603168 (Scopus)

Publication Title

IEEE Transactions on Electron Devices

External Full Text Location

https://doi.org/10.1109/TED.2005.857183

ISSN

00189383

First Page

2416

Last Page

2421

Issue

11

Volume

52

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