No abstract

The new metrology, Advanced Poly-silicon Ultra-Trace Profiling (APUTP), was developed for measuring bulk Cu and Ni in heavily boron-doped silicon wafers. A Ni recovery yield of 98.8% and a Cu recovery yield of 96.0% were achieved by optimizing the vapor phase etching and the wafer surface scanning conditions, following capture of Cu and Ni by the poly-silicon layer. A lower limit of detection (LOD) than previous techniques could be achieved using the mixture vapor etching method. This method can be used to indicate the amount of Cu and Ni resulting from bulk contamination in heavily boron-doped silicon wafers during wafer manufacturing. It was found that a higher degree of bulk Ni contamination arose during alkaline etching of heavily boron-doped silicon wafers compared with lightly boron-doped silicon wafers. In addition, it was proven that bulk Cu contamination was easily introduced in the heavily boron-doped silicon wafer by polishing the wafer with a slurry containing Cu in the presence of amine additives.

We have analysed the ALLEGRO data for the years 1999 and 2000 looking for continuous wave signals coming from some specific directions in the sky. No signal was found for these directions in long time integrations. However, we found a 'signal' at 919.535 Hz in a 50 min time integration search, which appeared on 13 August 1999 and disappeared on 12 December 1999. We present here the results of these searches and the reasons why we believe this 'signal' is probably noise.PACS numbers: 04.80.Nn, 95.55.Ym, 95.75−z

No abstract

We investigated the correlation between the junction leakagecurrent and bulk micro-defect (BMD) density for p-n + junctions fabricated on Czochralski (CZ) Si wafers. In order to measure BMD, the wafers were annealed at 800 o C for 4hr, followed by 1000 o C for 8, 16, and 24 hr in a N 2 ambient. After that, they were polished by 15 µm to remove the denuded zone (DZ) to disclose the BMD for detection using p-n + junctions. We confirm the junction depth and dopant concentration of the p-n + junctions by using secondary ion mass spectrometry (SIMS). After the electrical measurements we confirmed that the junction leakage current increases with increasing BMD density. The correlation factor between the junction leakage current and BMD density was about 99%.