Study of phosphorus doped Si:C films formed by in situ doped Si epitaxy and implantation process for n-type metal-oxide-semiconductor devices

Abstract

The effect of cluster carbon implantation and recrystallization on properties of phosphorus doped Si (Si:P) epitaxial films was investigated. Recrystallization techniques based on solid phase epitaxy with rapid thermal annealing (RTA), spike RTA (sRTA), and millisecond laser annealing were employed. It was found that strained carbon doped Si:P (Si:CP) layers with high [C]sub can be achieved by using low temperature sRTA/RTA due to the suppression of carbon-phosphorus coclustering in Si. Additional laser annealing can activate the remaining “nonactive” P atoms in the Si:CP layer recrystallized at low temperatures such as 900 °C sRTA and 800 °C 5 s RTA. This approach of combining a low temperature recrystallization anneal with an additional high temperature laser anneal was found to be useful for creating Si:CP layers with good crystallinity, low resistivity, and less phosphorus diffusion. Finally, a tensile strain was confirmed to be induced into the transistor channel by implementing the recrystallization technique on three dimensional fin-shaped field effect transistor device structures. A high recrystallization temperature of 1025 °C sRTA was found to be required for achieving complete recrystallization and suppressing introduction of defects/stacking faults in a Si:CP source/drain region.