Gate-First Negative Capacitance Field-Effect Transistor With Self-Aligned Nickel-Silicide Source and Drain

In this brief, we demonstrate the gate-first HfZrO2 (HZO) fully depleted silicon-on-insulator (FDSOI) negative capacitance field-effect transistor (NCFET) with self-aligned nickel-silicide (NiSi) source and drain (S/D). Although the gate-first process has advantages in terms of fabrication simplicity, the dopants of S/D cannot be fully activated since the polarization of ferroelectric HZO film is seriously degraded at high temperatures. To improve the S/D resistance without the polarization degradation, self-aligned S/D nickel silicidation, which induces dopant activation and dopant segregation at relatively low temperature, was simultaneously performed during ferroelectric post metal annealing (PMA). It is experimentally confirmed that 1) high concentrated dopants (As+) can be fully activated during silicidation through diode measurements and 2) S/D resistance can be reduced by NiSi silicidation through resistance measurements. Furthermore, it is verified that the electrical characteristic of NCFET with NiSi S/D exhibits superior current drivability without subthreshold swing (SS) degradation compared with that of NCFET without NiSi.