Device Characteristics of Ultra-shallow Junctions Formed by fRTP Annealing

The creation of ultra-shallow junction for CMOS devices at the sub-100 nm node is driving significant efforts in developing thermal processing to give rise to high dopant activation in combination with limited diffusion. Flash-assist Rapid Thermal Annealing™ (fRTP™) is a promising new annealing technique, which involves the heating of the bulk of the wafer to an intermediate temperature using rather conventional spike RTP, followed by a short and intense pulse of light localized on the implanted wafer surface.In this work, we have systematically investigated the junction formation of different implants under fRTP anneals in terms of profile and devices. Co-implanted Ge and F species provide more box-like profiles with improved activation. Although leakage currents are higher for fRTP-annealed junctions than for spike-annealed junctions, appropriate fRTP process parameters and correct process conditions provide a critical tool to control and reduce the leakage current of co-implanted fRTP junctions to acceptable levels. Proper implant and anneal are requested for minimizing pattern effect and improving device performance.