Reverse Diode Leakage in Spike-Annealed Ultra-Shallowjunctions


We have investigated diode leakage in junctions produced by ion-implantation of B with energies of 0.5 - 2 keV and doses of 2 × 1014 — 2 × 1015 cm-2 into n-type wells of ∼1 × 1018 cm-3, after rapid-thermal anneals (RTA) in lamp-based and hot-wall furnaces. Junc- tions are as shallow as 30nm and were directly probed to avoid complications arising from metalization. The leakage current, Ilkg, was found to be independent of the implant dose at any reverse voltage (-1 and -5 V). This implies that the electrically active defects are sufficiently far removed and on the surface-side of the junction. In both systems, a spike anneal (no intentional dwell time at peak-temperature) resulted in higher Ilkg than a soak anneal (dwell time of several seconds at peak-temperature). However, for the same spike annealing recipe, the hot-wall RTA produces tighter distributions than the lamp-based RTA. The width of the distribution is a mea- sure of the temperature uniformity across the wafer. Best leakage currents are of the order 1 × 10-6 A/cm2, in good agreement with device simulations The shallowest junctions exhibit Ilkg ∼5 × 10-4 A/cm2, still well below the specification of even the low power transistor of a 100 nm technology.

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Correspondence to Hans-Joachim.

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Hans-Joachim, Gossmann, L., Feng, T. et al. Reverse Diode Leakage in Spike-Annealed Ultra-Shallowjunctions. MRS Online Proceedings Library 669, 84 (2001).

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