Design of Hetero-Dielectric Single-Metal Gate-All-Around MOSFET with Schottky Contact Source/Drain

Abstract

One of the most promising device configurations for extending CMOS device scaling is the gate-all-around MOSFET since it provides excellent electrostatic control of the channel. In this work, hetero-dielectric single-metal gate-all-around MOSFETs with Schottky contact source/drain are designed and analyzed using COGENDA Visual TCAD. Through device simulations in a TCAD framework, the electrical properties of the devices, such as ON-current, leakage current, and subthreshold swing, have been examined. The proposed device features an unsymmetrical oxide geometry with Schottky source/drain regions and high-k (Hf_xTi_1−xO₂) on the source side (length dimension = 15 nm) and SiO₂ on the drain side (length dimension = 5 nm), respectively. The design of the suggested device has taken into account physical theories including drift–diffusion, Lombardi mobility, band-to-band tunneling, and the Shockley–Read–Hall carrier recombination process. The proposed device offers reduced OFF-current and suppressed SCEs. Compared to conventional GAA MOSFET, leakage currents are dropped to a level between 10⁻¹⁵ and 10⁻⁹ A. With a subthreshold swing of 62.7 mV dec⁻¹, which almost achieves the ideal value, the device exhibits impressive subthreshold region performance. It has exceptionally low static power consumption due to decreased leakages, which makes it ideal for low-voltage and low-power digital execution. According to device modeling analysis, the hetero-dielectric single-metal gate-all-around MOSFET with Schottky contact source/drain is a strong design for convenience in low-power digital circuitry.