Low resistance, low-leakage ultrashallow p+-junction formation using millisecond flash anneals

Junction formation using solid phase epitaxial (SPE) regrowth has been gaining popularity due to its high activation and low thermal budget which results in lower diffusion. Recently, it was shown that by carrying out the SPE regrowth at 1050°C using a single Flash from a millisecond annealing tool it is possible to obtain active concentrations as high as 6.5×10²⁰/cm³ (Flash SPE process)-much higher than low-temperature SPE-and near as implanted profiles. But the end-of-range (EOR) damage left beyond the amorphous-crystalline (a-c) interface results in poor leakage. We study the effect of a second Flash anneal at higher peak temperatures, and show that we can anneal out the EOR defects while causing minimal diffusion and deactivation of the B. This results in nearly two orders of magnitude reduction in leakage currents compared to a single Flash SPE.