F. Abbate

Combining metrology techniques for in-line control of thin SiGe:B layers

Abstract. A study performed to evaluate the benefits of combining techniques to improve the overall metrology of thin silicon germanium (SiGe) epitaxial layers doped with boron is presented. A specifically designed set of wafers was processed and measured by different in-line metrology tools and characterization techniques. This study describes the best strategy for combining metrology techniques in order to reliably determine dopant concentration and Ge composition measurement of the layers. It demonstrates that combined metrology enables key improvements in manufacturing and engineering environments.

In-line metrology capability for epitaxial multi-stack SiGe layers

This paper describes a study performed to evaluate inline metrology techniques for the monitoring of multiple SiGe layers in a manufacturing environment. Comparative measurements between High Resolution X-Ray Diffraction (HRXRD), X-Ray Reflectometry (XRR) and spectroscopic ellipsometry (SE) optical technique were carried out on a specifically-design wafer set. Strength and drawback of each technique are presented. An innovative approach of combining techniques for such application is explored and the results confirm the benefit of this strategy.

Benefit of combining metrology techniques for thin SiGe:B layers

This paper presents a study performed to evaluate the benefits of combining techniques to improve the overall metrology of thin Silicon Germanium (SiGe) epitaxial layers doped with Boron. A specifically-designed set of wafers was processed and measured by different in-line metrology tools and characterization techniques. This study describes the best strategy for combining metrology techniques in order to reliably determine dopant concentration and Ge composition measurement of the layers. It demonstrates that combined metrology enables key improvements in manufacturing and engineering environments.

Oxidation kinetics of Si and SiGe by dry rapid thermal oxidation, in-situ steam generation oxidation and dry furnace oxidation

The fabrication of ultrathin compressively strained SiGe-On-Insulator layers by the condensation technique is likely a key milestone towards low-power and high performances FD-SOI logic devices. However, the SiGe condensation technique still requires challenges to be solved for an optimized use in an industrial environment. SiGe oxidation kinetics, upon which the condensation technique is founded, has still not reached a consensus in spite of various studies which gave insights into the matter. This paper aims to bridge the gaps between these studies by covering various oxidation processes relevant to todays technological needs with a new and quantitative analysis methodology. We thus address oxidation kinetics of SiGe with three Ge concentrations (0%, 10%, and 30%) by means of dry rapid thermal oxidation, in-situ steam generation oxidation, and dry furnace oxidation. Oxide thicknesses in the 50 A to 150 A range grown with oxidation temperatures between 850 and 1100 °C were targeted. The present work shows first that for all investigated processes, oxidation follows a parabolic regime even for thin oxides, which indicates a diffusion-limited oxidation regime. We also observe that, for all investigated processes, the SiGe oxidation rate is systematically higher than that of Si. The amplitude of the variation of oxidation kinetics of SiGe with respect to Si is found to be strongly dependent on the process type. Second, a new quantitative analysis methodology of oxidation kinetics is introduced. This methodology allows us to highlight the dependence of oxidation kinetics on the Ge concentration at the oxidation interface, which is modulated by the pile-up mechanism. Our results show that the oxidation rate increases with the Ge concentration at the oxidation interface.The fabrication of ultrathin compressively strained SiGe-On-Insulator layers by the condensation technique is likely a key milestone towards low-power and high performances FD-SOI logic devices. However, the SiGe condensation technique still requires challenges to be solved for an optimized use in an industrial environment. SiGe oxidation kinetics, upon which the condensation technique is founded, has still not reached a consensus in spite of various studies which gave insights into the matter. This paper aims to bridge the gaps between these studies by covering various oxidation processes relevant to todays technological needs with a new and quantitative analysis methodology. We thus address oxidation kinetics of SiGe with three Ge concentrations (0%, 10%, and 30%) by means of dry rapid thermal oxidation, in-situ steam generation oxidation, and dry furnace oxidation. Oxide thicknesses in the 50 A to 150 A range grown with oxidation temperatures between 850 and 1100 °C were targeted. The present work sho...

Optical properties determination of Fully Depleted Silicon On Insulator (FDSOI) substrates by ellipsometry

We present an original experimental approach developed to extract with a good level of accuracy and confidence the optical properties of SOI layers for several thicknesses ranging from 3nm up to 12nm. The measurements were done using a spectroscopic ellipsometer in conjunction with an x-ray reflectometer. The instrumental function of the ellipsometer was first characterized experimentally to minimize systematic errors. A specific experimental protocol was then used to produce SOI Silicon layers and extract their optical properties. The resulting dispersion models were tested on other sample structures to check the validity of the models.