High-Performance Mixed-Mode Universal Min-Max Circuits for Nanotechnology

Abstract

In this paper a low-power, high-speed and high-resolution voltage-mode Min-Max circuit, as well as a new efficient universal structure for determining the minimum and maximum values of the input digital signals, is proposed for nanotechnology. In addition, the proposed designs provide rail-to-rail input and output signals which enhance the performance and the robustness of the circuits. The advantage of the proposed Min-Max circuit is that it is extendable for any arbitrary n-digit and radix-r input numbers. Comprehensive simulation results at CMOS and CNFET technologies demonstrate the low-power and high-performance operation as well as insusceptibility to PVT variations of the proposed structure.

An Efficient 5-Input Exclusive-OR Circuit Based on Carbon Nanotube FETs

“…This realistic model and circuit-compatible structure of the CNTFET considers nonidealities and various effects, such as inter-CNT charge screening effects, back-gate effects, SB effects at contacts, doped source-drain extension regions, and non-ideal nearballistic transport and device parasitic resistances and capacitances (Table 2) [21], [23]. The parameters of the conventional CMOS and CNTFET designs are set as (L, W) = (32 nm, 220 nm) and (D, N) = (1.5 nm, 5), respectively.…”

“…CNTFETs have similar structure and electrical characteristics to MOSFETs, which facilitates the exploitation and reuse of previous MOSFETbased architectures and fabrication processes [21]. P-CNTFET and N-CNTFET are the MOSFET-like CNTFETs [23]. The structure of a MOSFET-like CNTFET is demonstrated in Fig.…”

“…Another essential characteristic of CNTFET is its flexible behavior in manipulating the threshold voltage (V th ) by adopting a proper diameter for CNTs [17]. There are three types of CNTFET: The first type is the MOSFET-like CNTFET (includes the p-type CNTFET [P-CNTFET] and n-type CNTFET [N-CNTFET]), which operates in a unipolar fashion; The second type is the Schottky barrier (SB) CNTFET, which demonstrates ambipolar characteristics [31] but is not proper for ultra high-performance applications because of the SB element; The third type of CNTFET, suitable for ultra lowpower applications, is the band-to-band tunneling CNTFET and has significantly low current in its active mode [23]. The CNTFET has relatively low off-current whenever the transistor is inactive; in other words, when the CNTFET is off, leakage power consumption is very low [18].…”

“…P-CNTFET and N-CNTFET are the MOSFET-like CNTFETs [23]. The structure of a MOSFET-like CNTFET is demonstrated in Fig.…”

“…According to Moore's law, it can be concluded that the bulk-silicon transistor should be replaced by a promising alternative device in the near future [19]. Therefore, possible replacements for CMOS technology, including the single-electron transistor, the quantum-dot cellular automaton, molecular devices (benzene rings), and the carbon nanotube field effect transistor (CNTFET), are under investigation [23]- [25]. Among these alternative technologies, the CNTFET is the most encouraging substitution for the conventional MOSFET family due to its similarities to MOSFET in terms of electrical properties and manufacturing process [26].…”