22 nm Node p+ USJ Formation Using PAI & HALO Implantation With Laser Annealing

Abstract

Boron 200 eV p+ USJ dopant activation and junction leakage was studied with various combinations of PAI (Ge, B36, In & Xe) and HALO (As & Sb) implantation using msec laser annealing between 1220 °C and 1350 °C. For B only case without PAI or HALO, increasing laser anneal temperature from 1220 °C to 1350 °C improved dopant activation boron solid solubility (Bss) from 3E19/cm3 to 1.2E20/cm3 with excellent junction leakage below the lower detection limit of <1E‐7A/cm2. Deep Ge‐PAI improved dopant activation Bss by 4x to 1.2E20/cm3 at 1220 °C and degraded junction leakage by >10x due to residual implant damage (EOR defects) beyond the junction. Higher laser anneal temperatures up to 1350 °C improved junction leakage to below detection limit and Bss improved to 1.4E20/cm3. With deep Xe‐PAI junction leakage was severely degraded by 5 orders of magnitude to above the upper detection limit of >2.5E‐2A/cm2 but with annealing temperatures >1300 °C junction leakage improved, at 1350 °C junction leakage improved to 8E‐5A/cm2 and Bss to 1.5E20/cm3. With shallower PAI junction leakage improved but at the expense of dopant activation at lower MSA temperatures <1300 °C but the 3 keV Ge‐PAI dopant activation and leakage was similar to molecular B. With the presence of either As or Sb HALO structure, >5 orders of magnitude degradation in junction leakage current was detected (>2.5E‐2A/cm2) and higher laser anneal temperatures of 1320 °C was needed to improve dopant activation and junction leakage. However, the combination of Sb‐HALO with In‐PAI gave the best optimized Bss >4E20/cm3 and low leakage <1E‐5A/cm2.