Papers by Author: Koichiro Saga

Abstract: We have found that to the detection sensitivity of Total reflection X-ray fluorescent spectrometry (TXRF), the total volume of trace particles generated by vapor phase treatment (VPT) must be increased and metal atoms need to be included in the particles. The detection sensitivity for Cu is enhanced by assisting Cu ionization in the liquid drops condensed form the vapor. We consider that since incident and reflected X-rays resonate 30nm from the surface, the total reflection intensity of metals included in the particles is enhanced.

Abstract: We studied the detection by TXRF of several transition metals on the surface of III-V materials for high mobility channel. It has been found that the lower limits of detection of some transition metals on the surface of III-V materials become higher than that on the Si surface because the sum peaks or Raman scattering peaks as well as the fluorescent X-ray main signals from the materials themselves partially cover those from the transition metals

Abstract: Metallic contamination on silicon surfaces has a detrimental impact on the performance and yield of ULSI devices. Surface metal impurities degrade the gate oxide integrity while metal impurities dissolved in silicon cause recombination centers and this results in junction leakage. The diffusion behavior of these metal impurities in silicon is well-known [1]. On the other hand, these metal impurities often penetrate the silicon through the silicon oxide or silicon nitride films in ULSI processing. The surface metal impurities penetrate the silicon by colliding with the dopant during ion implantation and are also diffused in silicon by subsequent annealing [2]. While the diffusion behavior of the metal impurities penetrating silicon substrates through the silicon oxide films has been reported [3], little work has been reported on the diffusion behavior of the metal impurities penetrating silicon nitride films. We demonstrated the diffusion behavior of the metal impurities penetrating silicon substrates through a CVD SiN film due to the collision with dopant during ion implantation.

Abstract: Metallic contamination on silicon surfaces has a detrimental impact on ULSI device performance and yield. Surface metal impurities degrade gate oxide integrity while metal impurities dissolved in silicon cause recombination centers and result in junction leakage. Surface metal impurities penetrate silicon by the colliding with dopant during ion implantation and are also diffused in silicon by subsequent annealing [. The diffusion behavior of metal impurities in silicon is well-known [. While metal impurities often penetrate silicon through the silicon oxide in ULSI processing, little work has been reported on the diffusion behavior of metal impurities penetrating silicon oxide. We demonstrated the diffusion behavior of metal impurities penetrating silicon substrates with different thickness of silicon oxide by the collision with dopant during ion implantation.

Abstract: Metallic contamination on silicon surfaces has a detrimental impact on ULSI device performance and yield. Surface metal impurities degrade gate oxide integrity, while metal impurities dissolved in silicon provide recombination centers, resulting in junction leakage. Surface metal impurities penetrate silicon by the collision with dopant during ion implantation and are also diffused in silicon by subsequent annealing [. If metal impurities are present around junctions, they can cause junction leakage. In order to avoid the junction leakage, metal impurities must be away from junction. It was reported that iron can be gettered in the region of dopants implanted at high energy [. On the other hand, little work has been reported on the behavior of metal impurities in shallow junction. In this study, the gettering behavior of various transition metals in low-energy and high-dose ion-implanted silicon has been demonstrated.