Steep Subthreshold Swing in GaN Negative Capacitance Field-Effect Transistors

Abstract

Due to the Boltzmann distribution of carriers, the subthreshold swing (SS) of traditional metal-oxide- semiconductor field-effect transistors (MOSFETs) is above 60 mV/dec at room temperature. In this article, GaN-based negative capacitance field-effect transistors (NCFETs) were fabricated by introducing HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /P(VDF-TrFE) stack as the gate dielectric layer. With the voltage amplification effect of the ferroelectric, the GaN NCFETs demonstrate the ultralow SS value of 36.3 mV/dec at room temperature, which also advances the MOSFETs in terms of saturation current (633.4 μA/μm) and ON - OFF ratio (> 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> ). Therefore, this article demonstrates the feasibility of NCFETs for breaking the Boltzmann limit in III-V semiconductors-based transistors and opens up an avenue for switching electronic devices for portable applications.