M. Alper Sahiner

Characterizing crystalline polymorph transitions in HfO2 by extended x-ray absorption fine-structure spectroscopy

Atomic layer deposited HfO2 films on Si(100) substrates have been measured by extended x-ray absorption fine-structure (EXAFS), pre- and postanneal processing. Analysis of the second coordination shell indicates an increase in atomic order with increasing film thickness for each anneal temperature and with increasing anneal temperature for each film thickness. Fourier transformed EXAFS spectra fit with HfO2 reference phases have identified orthorhombic to tetragonal to monoclinic transformations. Evidence for greater retention of the higher permittivity metastable tetragonal phase corresponding to thinner HfO2 films is consistent with a surface energy effect giving rise to the critical grain size phenomenon.

Clustering Analysis in Boron and Phosphorus Implanted (100) Germanium by X-Ray Absorption Spectroscopy

Recently, germanium based semiconductor device technology gained renewed interest due to new developments such as the use of high- k dielectrics for high mobility Ge MOSFETS. However, a systematic local structural investigation of clustering of dopants has been lacking in the literature. In this study, we present a detailed local structural analysis of boron and phosphorus implanted Ge wafers. We have used Ge K-edge x-ray absorption fine-structure spectroscopy (XAFS) in order to probe the local structural modifications around the Ge atom under various implantation parameters and postimplantation annealing treatments. The (100) Ge wafers were implanted and with 11 B + or 31P+ using energies ranging from 20 keV to 320 keV and doses of 5×10 13 to 5×10 16 /cm 2 . Pieces of the implanted wafers were subjected to thermal annealing at 400°C or 600°C for three hours in high purity nitrogen. Secondary ion mass spectrometry (SIMS) measurements on these wafers were used to correlate the dopant concentration profiles with the local structural information obtained from XAFS. B and P implanted Ge exhibit distinct responses to annealing. For the P implanted Ge samples annealing leads to recrystallization of Ge with increasing annealing temperature, but also an increase in Ge Debye-Waller factors, whereas B implanted Ge samples e×hibit recrystallization at 400°C annealing but more randomness after 600°C annealing.

Characterization of Local Structures in Plasma Deposited Semiconductors by X-ray Absorption Spectroscopy

Extended X-ray-Absorption Fine-Structure Spectroscopy (EXAFS) has been used to investigate the subtle local structural variations in plasma deposited semiconductors. Grazing incidence geometry EXAFS is a very effective tool to study the surface layers. Since EXAFS is an element specific sensitive local structural probe, it is advantageous to commonly used structural characterization techniques where there is no long-range crystalline order in material. EXAFS can provide crucial information deposition or post-deposition induced crystallographic structural modifications. The information extracted from EXAFS can be used as an important feedback for the thin film growth mechanisms. In this chapter the fundamental principles of EXAFS will be introduced. The data reduction and analyses with the structural model calculations will be discussed. The application of the EXAFS in plasma deposited silicon wafers and plasma-plume deposited high-k dielectric thin films will be presented.

The local structural characterization of the inactive clusters in B, BF2 and BF3 implanted Si wafers using X-ray techniques

Abstract Characterization of the inactive clusters formed by high dose implantation silicon are one of the crucial topics in the semiconductor industry. Analytical techniques, which could provide quantitative information on the detailed description of the complexes that are formed at dopant concentrations above solid solubility levels, are valuable to post-implantation researchers. Previously, X-ray absorption fine-structure spectroscopy (XAFS) studies of the As and Sb implanted Si wafers revealed not only that of the chemical nature of clusters, but also the arsenic case, the ratio of the precipitated versus the substitutional form of the As in the system [1] , [2] . In this study, we have used F K-edge and Ge K-edge (for the Ge pre-amorphized wafers) XAFS in order to probe the nature and of the clusters in B, BF2 and BF3 implanted Si wafers. Implants with various doses and implant energies were subjected to various annealing techniques such as laser annealing, spike annealing, solid state phase epitaxy, and flash annealing and the evolution of the spectral features of the clusters were followed upon annealing. The theoretical multiple scattering XAFS calculations were performed in order to correlate the spectral features in the XAFS data with the near-neighbor configuration around the main absorbing atom. The identification and the relative weight of the clusters after different annealing conditions will be presented in order to provide insight to the optimum annealing conditions in these systems.

The Role Of Ge In Cluster Formation In B And Bf 2 Implanted Si Wafers After Ge Pre-Amorphization

Cluster formation in high dose B, BF2 implanted Si wafers is an important problem in silicon doping, since it is one of the leading causes of the electrical deactivation of the dopant. In this study, we used Ge pre-amorphized, ultra low energy B and BF2 implanted Si wafers in order to probe these clusters from a local structural point of view. Ge K-edge x-ray absorption spectroscopy (XAFS) is a powerful tool in obtaining local structural information around the Ge atom. The effects of different implant species with various implant doses and annealing conditions on the cluster formation are presented using Ge K-edge multi-shell XAFS analysis. The non-linear least-squares fits to the Ge K-edge Fourier Transformed (FT) XAFS data using calculated standards from multiple scattering simulations around the Ge atom reveal formed Ge-B clusters for the Rapid Thermal Processing (RTP) annealed wafers. The results also indicate the laser annealing process on the other hand is blocking the formation of these Ge induced Ge-B clusters.

Non-routine Dopant, Impurity and Stoichiometry Characterization of SiGe, SiON and Ultra-low Energy B-implanted Si Using Secondary Ion Mass Spectrometry

New, non-routine metrology issues are addressed for three kinds of materials and processes that are necessary for the fabrication of ultra-high speed devices. We look at the problems and solutions for measuring both stoichiometry and dopant content of SiGe material when using Cs primary ion bombardment. We examine the challenges of determining the N content of ultra-thin SiON gate dielectrics with emphasis on what will be necessary for the measurement of 1nm thick oxides. And finally we show some promising early results of using a new protocol for measuring ULE B ion implant profiles in the top 3nm with emphasis on obtaining a more realist profile shape in this region for TCAD modeling purposes.