Reverse Diode Leakage-Annealed Ultra-Shallow Junctions

We have investigated diode leakage in junctions produced by ion-implantation of B with energies of 0.5 - 2 keV and doses of 2 x 10 sup 14 - 2 x 10 sup 15 cm sup -2 into n-type wells of ~1 x 10 sup 18 cm sup -3 , after rapid-thermal anneals (RTA) in lamp-based and hot-wall furnaces. Junctions are as shallow as 30 nm and were directly probed to avoid complications arising from metalization. The leakage current, I sub lkg , 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 active defects are sufficiently far removed and on the surface-side of the junction. In both systems, a spike 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 measure of the temperature uniformity across the wafer. Best leakage currents are of the order 1 x 10 sup -6 A/cm sup 2 , in good agreement with device simulations. The shallowest junctions exhibit I sub lkg ~ 5 x 10 sup -4 A/cm sup 2 , still well below the specification of even the low power transistor of a 100 nm technology.