Fin Doping by Hot Implant for 14nm FinFET Technology and Beyond

Fin Doping by Hot Implant for 14nm FinFET Technology and Beyond B. Wood, F. Khaja, B. Colombeau, S. Sun, A. Waite, M. Jin, H. Chen, O. Chan, T. Thanigaivelan, N. Pradhan, H.-J. Gossmann, S. Sharma, V. Chavva, M-P Cai, M. Okazaki, S. Munnangi, C-N Ni, W. Suen, C-P Chang, A. Mayur, N. Variam, and A. Brand Applied Materials, Silicon Systems Group, Sunnyvale, CA 96085 The transition from a planar to a FinFET device structure has changed device doping requirements. The fin sidewall doping and activation, crystallinity control of the fin, junction profile and leakage control on the fin are new challenges. With continuous scaling of FinFET technology, the narrower fins become more prone to crystallinity damage by ion implant, and lead to increases in junction leakage and fin parasitic resistance. We have introduced hot implant as a superior doping technique to room-temperature implant for arsenic source drain extension (SDE) and halo implants on vertical narrow fins. We have demonstrated for the first time that hot SDE implant on 6nm CD vertical fins produced single crystalline fins and enabled 5x improvement in fin line resistance and more than 10x reduction in junction leakage compared with a room-temperature SDE implant. Introduction FinFET technology has been introduced starting at the 22nm technology node to suppress device short channel effects (SCE) (1). The fin and the gate critical dimensions (CD) will continue to scale in each technology node and the channel material may move to group IV other than Si and III-V materials in the future. The narrow fins improve device SCE control. To achieve optimal device drive current, the SDE sheet resistance needs to be minimized. Ion implantation is the leading candidate for junction formation with the advantages of precision dose and energy control, which enable precision tuning of transistor performance and reduced device variability. The traditional arsenic ion implant for n-SDE with low energy and high dose can fully amorphize the narrow fin, resulting in damaged fin crystallinity upon activation anneal (2), and lead to high parasitic resistance and junction leakage. The amorphization is the result of a critical balance between damage generation and annihilation (3). Increasing substrate temperature during ion implant enhances defect annihilation or dynamic anneal, which increases the dose threshold for the onset of amorphization. We have introduced hot implant for damage-free arsenic (As) fin SDE doping and halo doping. Below a fin width threshold at about 15nm where the RT arsenic implanted fin became polycrystalline after activation anneal, hot implant improved fin conductance by 5x and junction leakage by >10x. Hot As