Performance optimization of GaAs NCFET with a complex oxide ferroelectric gate ​

Abstract

In this work, we try to design a high-performance GaAs NCFET with ferroelectric 0.85BiTi0.1Fe0.8Mg0.1O3-0.15CaTiO3 (BTFM-CTO) gate dielectric. A detailed simulation was first made on GaAs NCFET to clarify the influence of key structural factors on the performance of NCFET. Simulation results indicate these factors have effects on capacitances match. Moreover, key factors will also affect the device performance and result in the variation of some effects such as negative differential resistance (NDR), gate voltage amplification (GVA), short channel effect (SCE), and saturation of carrier mobility (SCM). These effects influence and constraint each other. The competition between these effects makes the performance not monotonously vary with factors and highly depends on other parameters or voltage bias. Mobility, band energy diagram, electric potential along channel surface, and substrate capacitance are then investigated to make detailed analyses of simulation results. These simulation results and analysis are valuable to optimize NCFET and adjust the drive strength of NCFET with a given ferroelectric film, which would benefit the further application of NCFET. Finally, optimization of the NCFET with BTFM-CTO has been done. A steep SS value of 44.9 mV/dec and a high ION/ IOFF value of 1.2×109 is achieved with a low supply voltage of 0.6 V, demonstrating that the BTFM-CTO film is a competitive candidate for a ferroelectric layer applied in GaAs NCFET. The current work may generate new insights into advanced NCFET based on GaAs with high ION/ IOFF.