Ferroelectric Negative Capacitance GeSn PFETs With Sub-20 mV/decade Subthreshold Swing

Negative capacitance (NC) GeSn pFETs integrated with HfZrOx(HZO) ferroelectric film is demonstrated with sub-20 mV/decade subthreshold swing (SS) over two orders of magnitude of IDS. The ratio of remnant polarization to coercivity in HZO is significantly improved with the increasing of the annealing temperature from 400°C to 500°C, which contributes to the effective reduction of hysteresis in ferroelectric NC GeSn transistors. Ferroelectric NC GeSn pFET annealed at 500°C achieves a hysteresis of 70 mV while maintaining a steep SS dramatically lower than 60 mV/decade, and an improved IDS over control device without HZO.