Hoelzl, R. and Range, Klaus-Jürgen and Fabry, L. (2002) Comparison of different gettering techniques for Cu-p plus versus polysilicon and oxygen precipitates. APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 75 (5). pp. 591-595. ISSN 0947-8396
Full text not available from this repository.Abstract
We performed measurements of gettering efficiencies for Cu in silicon wafers with competing gettering sites. Epitaxial wafers (p/p+) boron-doped with a polysilicon back side allowed us to compare p+ gettering with polysilicon gettering. We further measured metal distributions in p+/p- epitaxial test wafers, with the p- substrate wafers pretreated for oxygen precipitation to compare p+ Bettering with oxygen precipitate gettering. Our test started with a reproducible spin-on contamination in the 10(12) atoms/cm(2) range, followed by thermal treatment in order to redistribute the metallic impurity. Wafers were then analyzed by a novel wet chemical layer-by-layer etching technique in combination with inductively coupled plasma mass spectrometry. This led to "stratigraphical" concentration profiles of the impurity, with typical detection limits of 5-10 x 10(12) atoms/cm(3). Twenty-five percent of the total Cu contamination in the p/p+/poly wafer was found in the p+ layer, whilst 75% was gettered by the polysilicon. Obviously, polysilicon exhibits a stronger gettering than p+ silicon, but due to the large distance from the front surface, polysilicon was less effective in reducing impurities from the front side of a wafer compared with p+ gettering. An epitaxial layer p+ on top of p- substrates with oxygen precipitates gettered 50% of the total Cu; while the other 50% of the Cu was measured in the p- substrate wafer with oxygen precipitates. Without oxygen precipitates, 100% of the spiked Cu contamination was detected inside the p+ layer. Gettering by oxygen precipitates thus occurs in the same temperature range as that where p+ silicon begins to getter Cu.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SILICON-WAFERS; COPPER; DIFFUSION; CONTAMINATION; LIFETIME; FE; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Anorganische Chemie > Alumni or Retired Professors > Prof. Dr. Klaus-Jürgen Range |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 25 Aug 2021 12:31 |
| Last Modified: | 25 Aug 2021 12:31 |
| URI: | https://pred.uni-regensburg.de/id/eprint/39700 |
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