Formation of 0.05-μm p+-n and n+-pjunctions by very low (<500 eV) ion implantation |
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Authors: | Bousetta A. van den Berg J.A. Armour D.G. |
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Affiliation: | Dept. of Electr. Eng., Salford Univ.; |
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Abstract: | The current-voltage (I-V) characteristics of ultrashallow p+ -n and n+-p diodes, obtained using very-low-energy (<500-eV) implantation of B and As, are presented. the p+-n junctions were formed by implanting B+ ions into n-type Si (100) at 200 eV and at a dose of 6×1014 cm-2, and n+-p junctions were obtained by implanting As+ ions into p-type (100) Si at 500 eV and at a dose 4×1012 cm-2. A rapid thermal annealing (RTA) of 800°C/10 s was performed before I-V measurements. Using secondary ion mass spectrometry (SIMS) on samples in-situ capped with a 20-nm 28Si isotopic layer grown by a low-energy (40 eV) ion-beam deposition (IBD) technique, the depth profiles of these junctions were estimated to be 40 and 20 nm for p+-n and n+-p junctions, respectively. These are the shallowest junctions reported in the literature. The results show that these diodes exhibit excellent I-V characteristics, with ideality factor of 1.1 and a reverse bias leakage current at -6 V of 8×10-12 and 2×10-11 A for p+-n and n+-p diodes, respectively, using a junction area of 1.96×10-3 cm2 |
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