Steep switching devices for low power applications: negative differential capacitance/resistance field effect transistors

Abstract

Simply including either single ferroelectric oxide layer or threshold selector, we can make conventional field effect transistor to have super steep switching characteristic, i.e., sub-60-mV/decade of subthreshold slope. One of the representative is negative capacitance FET (NCFET), in which a ferroelectric layer is added within its gate stack. The other is phase FET (i.e., negative resistance FET), in which a threshold selector is added to an electrode (e.g., source or drain) of conventional field effect transistor. Although the concept of the aforementioned two devices was presented more or less recently, numerous studies have been published. In this review paper, by reviewing the published studies over the last decade, we shall de-brief and discuss the history and the future perspectives of NCFET/phase FET, respectively. The background, experimental investigation, and future direction for developing the aforementioned two representative steep switching devices (i.e., NCFET and phase FET/negative resistance FET) are to be discussed in detail.

The Concept of Negative Capacitance in Ionically Conductive Van der Waals Ferroelectrics

“…NC provides the intriguing opportunity to operate transistors at voltages below the 60 mVper-decade limit (a benchmark number to describe current-voltage characteristic of field effect transistors) imposed by the Boltzmann distribution of electrons, allowing for a significant reduction in power consumption and waste heat in electronic devices. [1][2][3][4][5][6][7][8][9] As a result, NC devices based on ferroelectric materials have attracted significant scientific attention. Such devices, however, are discussed in the context of quasi-static or transient NC phenomena.…”

Steep Switching of In0.18Al0.82N/AlN/GaN MIS-HEMT (Metal Insulator Semiconductor High Electron Mobility Transistors) on Si for Sensor Applications

“…Intel exhibits a near ideal 60 mV/dec of subthreshold swing for MIS-HEMT enhancement mode, and a depletion mode device with steep SS < 60 mV/dec because of “negative” capacitance effect is shown using an AlInN metal-oxide-semiconductor (MOS) HEMT on SiC [10]. The negative capacitance concept is already demonstrated for steep switching on the Complementary Metal-Oxide-Semiconductor (CMOS) platform, including experimental and simulation development [11]. In general, the barrier layer with incorporated In exhibits a steep switch slope, ultra-low drain current leakage floor, and high ON/OFF ratio when compared with AlGaN barriers.…”

Atomic threshold-switching enabled MoS2 transistors towards ultralow-power electronics

“…However, CMOS technology still faces a great challenge of feature size <5 nm, due to the degradation of the off-state leakage current induced by short-channel effects (i.e., direct source-drain punch through, and a loss of gate electrostatic control) [3][4][5][6][7][8] . An efficient way to minimize power consumption is to achieve a steep subthreshold swing (SS) with a fast-switching rate at a reduced supply voltage 7,9 . The emerging two-dimensional (2D) transition metal dichalcogenides [10][11][12] , e.g., atomically thin molybdenum disulfide (MoS 2 ) 5,8,13 , are promising channel materials for future electronic chips with scaling dimensions and ultralow off-state currents, due to the high electron effective mass, low dielectric constant, and large bandgap [10][11][12][13] .…”

“…The demonstrated threshold-switching behavior acting as an internal amplifier offers a shortcut to conquer the Boltzmann limit and triggers the FET to switch with a sub-kT/q slope. In particular, the NDR effect in threshold-switching FET is highly predictable and quantifiable for constructing steeply switchable electronic devices with high performance 9,21 . When compared to a common insulator-metal-transition device (e.g., VO 2 ) 21,23 , a new type of metal filamentary threshold switch (TS), which generally consists of Ag (or Cu) as an active electrode or dopant in a solid electrolyte, has been demonstrated a lower leakage current and much steeper switching characteristics [24][25][26][27] , and can contribute to suppressing the off-state leakage current of conventional FETs with an abrupt SS 22,28 .…”