Title :
Dual workfunction Ni-Silicide/HfSiON gate stacks by phase-controlled full-silicidation (PC-FUSI) technique for 45nm-node LSTP and LOP devices
Author :
Takahashi, Kensuke ; Manabe, Kenzo ; Ikarashi, Taeko ; Ikarashi, Nohuyuki ; Hase, Takashi ; Yoshihara, Takuya ; Watanabe, Heiji ; Tatsumi, Tom ; Mochizuki, Yoshihiro
Author_Institution :
Syst. Devices Res. Labs., NEC Corp., Kanagawa, Japan
Abstract :
We present a new threshold-voltage (Vth) control technique for fully-silicided (FUSI) metal/high-k gate stacks which are suitable for 45nm-node LOP and LSTP CMOS. The key is the phase control of FUSI Ni-silicide by changing Ni film thickness prior to silicidation anneal. As a result, Ni3Si and NiSi2 are formed whose effective workfunctions (WFs) on HfSiON are found to be 4.8eV and 4.4eV, respectively, being largely displaced from Si-midgap by ±0.2eV. Meanwhile, the dopant segregation method, known to be successful in Vth-control of NiSi on SiO2, did not work on HfSiON. With Ni3Si-PMOS and NiSi2-NMOS transistors, a wide range of Vth-tuning is achieved coping with both LSTP and LOP requirements. At the same time, leakage suppression merit is better than the 45nm-node targets at electrical thickness (Tinv) around 2.0 nm. Also, our phase-controlled fully silicided (PC-FUSI) devices show excellent mobility characteristics.
Keywords :
CMOS integrated circuits; MOSFET; phase control; voltage control; work function; LOP CMOS; LOP devices; LSTP CMOS; LSTP devices; NMOS transistor; Ni-silicide-HfSiON/int; Ni3Si; NiSi; PMOS transistor; SiO2; dual workfunction; effective workfunctions; gate stacks; mobility characteristics; phase control; phase-controlled full-silicidation technique; silicidation anneal; voltage control technique; Annealing; Capacitance-voltage characteristics; Control systems; Dielectrics; Laboratories; MOS devices; National electric code; Phase control; Silicidation; Silicides;
Conference_Titel :
Electron Devices Meeting, 2004. IEDM Technical Digest. IEEE International
Print_ISBN :
0-7803-8684-1
DOI :
10.1109/IEDM.2004.1419074