Twist's Review #7 - Antiferroelectric NCFET

Paper: Antiferroelectric Negative Capacitance
Transistor for Low Power Consumption

Previously I reviewed a paper discussing epitaxial fabrication of ferroelectric HfO2/HZO using Pulse Laser Deposition. A phenomenon closely related to ferroelectricity is antiferroelectricity where the dipoles inside the material will be opposite of each adjacent line of dipoles. While antiferroelectricity can also occur with HfO2, this paper makes use of antiferroelectricity in PbZrO3. The antiferroelectricity in PbZrO3 can be utilised to make negative capacitance devices, devices that will aid in making low power consumption devices. My first review was on AlScN NCFET with a 2D MoS2 channel, where this paper shows a PbZrO3 NCFET with an IGZO (InGaZnOx) channel, another up and coming semiconductor channel.

In this paper the PbZrO3 is paired with a HfO2, achieving an EOT of 0.79 nm compared to 2.1 nm with only HfO2 as a result of the negative capacitance. The fabricated NCFET showed lower off current (1e-13) compared to a regular HfO2 insulated transistor (1e-11) and hs a much steeper slope. The NCFET achieves SS below 60 mV/dec below around 1e-12 A/um with almost hysteresis-free operation (6 mV). Hysteresis is a massive problem for logic devices, so this small hysteresis is a good sign for future work.

Reference: L. Qiao et al., “Antiferroelectric Negative Capacitance Transistor for Low Power Consumption,” in IEEE Electron Device Letters, vol. 45, no. 1, pp. 52-55, Jan. 2024, doi: 10.1109/LED.2023.3330451.

Another NCFET device using a different material. I think it is important to know how different materials can perform to make devices that aim to do the same thing, just like how there are many different materials for power electronics based on wide bandgap semiconductors. The field of ferroelectricity for electronic devices is one I would love to delve into, and I just got to know of this material for NCFET so this was an interesting read.

Again, many things can be investigated here such as the usage of HfO2 and IGZO as compared to other reports. For example my first review was AlScN based with MoS2 channel and in that paper HfOx showed the best performance as a gate oxide which may be show that these papers are in agreement.