0000000000185602
AUTHOR
Simone Giangrandi
Time-of-flight telescope for heavy-ion RBS
Abstract This paper describes a time-of-flight (TOF) spectrometer for Heavy-Ion Rutherford Backscattering Spectrometry (HI-RBS) recently installed at IMEC for thin film analysis. The TOF telescope allows the use of ion beams heavier than He, with advantages in terms of depth and mass resolution and sensitivity compared to conventional RBS based on planar Si detectors. The start timing-signal is produced by the secondary electrons emitted from a thin C foil when traversed by a backscattered ion; the electrons are deflected in an electrostatic mirror towards a Micro-channel plate (MCP) assembly which provides a fast timing response. The stop signal is obtained directly from a second MCP assem…
Depth resolution optimization for low-energy ERDA
Abstract With the implementation of low-energy time-of-flight Elastic Recoil Detection Analysis (ERDA), routine analysis of thin films with high depth resolution becomes possible. The optimization of the measurement conditions is a key issue for an accurate sample characterization and is normally a compromise among depth resolution, mass resolution and sensitivity, for a given sample. In this work, we focus on the depth resolution optimization, presenting an extensive study of two different materials, SiO 2 and TiN, representative of light and medium mass targets. The film thickness varies between 10 and 50 nm. The samples were measured with different beams ( 35 Cl, 63 Cu, 79 Br and 127 I),…
Irradiation-induced damage in porous low-k materials during low-energy heavy-ion elastic recoil detection analysis
Abstract With the implementation of time-of-flight elastic recoil detection (ToF-ERD) for the analysis of thin films with high depth resolution using a standard ‘low-energy’ accelerator, routine application of ERD in semiconductor technology becomes possible. In case of irradiation-sensitive materials, like organosilicate low- k films, the energetic incident beam damages the sample during the measurement, resulting in loss of the lighter elements and, as a consequence, altering the sample composition. The ion beam induced damage is investigated for 19 F, 35 Cl, 63 Cu, 79 Br and 127 I beams at energies of 6–16 MeV and typical fluences for ERD analysis. By means of Fourier transform infrared …
Considerations about multiple and plural scattering in heavy-ion low-energy ERDA
Abstract Low-energy heavy-ion Elastic Recoil Detection Analysis (ERDA) is becoming a mature technique for high-resolution characterization of thin films, i.e. below 50 nm thickness. In combination with a small tandem accelerator (∼2 MV terminal voltage) and beam energies below 20 MeV, it is suitable for routine analysis of key materials in semiconductor technology. At low-energies, however, small angle multiple scattering and large angle plural scattering of ions play a significant role, starting from the first nanometers. Multiple and plural scattering dominate the depth resolution deterioration with increasing depth and, when glancing angles are used, introduce long tails in the elemental…
Low-energy heavy-ion TOF-ERDA setup for quantitative depth profiling of thin films
Abstract Low-energy heavy-ion time-of-flight elastic recoil detection analysis (TOF-ERDA) is becoming a mature technique for accurate characterization of thin films. In combination with a small tandem accelerator (∼2 MV terminal voltage) and beam energies below 20 MeV, it is suitable for routine analysis of key materials in semiconductor technology. In this paper we discuss advantages and drawbacks of low-energy ERDA, compared to high-energy ERDA, in terms of depth and mass resolution, detection efficiency for light elements, sample irradiation damage and quantification accuracy. The results presented are obtained with the time-of-flight telescope recently developed at IMEC. The time-of-fli…
Analysis of thin high-k and silicide films by means of heavy ion time-of-flight forward-scattering spectrometry
The use of forward scattered heavy incident ions in combination with a time-of-flight-energy telescope provides a powerful tool for the analysis of very thin (5–30 nm) films. This is because of greater stopping powers and better detector energy resolution for heavier ions than in conventional He-RBS. Because of the forward scattering angle, the sensitivity is greatly enhanced, thus reducing the ion beam induced desorption during the analysis of very thin films. The drawback of forward scattering angle is the limited mass separation for target elements. We demonstrate the performance of the technique with the analysis of 25 nm thick NiSi films and atomic layer deposited 6 nm thick HfxSiyOz f…