Understanding the Potential and Limitations of Tunnel FETs for Low-Voltage Analog/Mixed-Signal Circuits

In this paper, the analog/mixed-signal performance is evaluated at device and circuit levels for a III-V nanowire tunnel field effect transistor (TFET) technology platform and compared against the predictive model for FinFETs at the 10-nm technology node. The advantages and limits of TFETs over their FinFET counterparts are discussed in detail, considering the main analog figures of merits, as well as the implementation of low-voltage track and-hold (T/H) and comparator circuits. It is found that the higher output resistance offered by TFET-based designs allows achieving significantly higher intrinsic voltage gain and higher maximum-oscillation frequency at low current levels. TFET-based T/H circuits have better accuracy and better hold performance by using the dummy switch solution for the mitigation of the charge injection. Among the comparator circuits, the TFET-based conventional dynamic architecture exhibits the best performance while keeping lower area occupation with respect to the more complex double-tail circuits. Moreover, it outperforms all the FinFET counterparts over a wide range of supply voltage when considering low values of the common-mode voltage

A Study on the Effect of the Structural Parameters and Internal Mechanism of a Bilateral Gate-Controlled S/D Symmetric and Interchangeable Bidirectional Tunnel Field Effect Transistor

A bilateral gate-controlled S/D symmetric and interchangeable bidirectional tunnel field effect transistor (B-TFET) is proposed in this paper, which shows the advantage of bidirectional switching characteristics and compatibility with CMOS integrated circuits compared to the conventional asymmetrical TFET. The effects of the structural parameters, e.g., the doping concentrations of the N+ region and P+ region, length of the N+ region and length of the intrinsic region, on the device performances, e.g., the transfer characteristics, Ion–Ioff ratio and subthreshold swing, and the internal mechanism are discussed and explained in detail.The Natural Science Foundation of Liaoning Province No. 2019-MS-250. This fund is used to pay for the publication of papers

Digital and analog TFET circuits: Design and benchmark

In this work, we investigate by means of simulations the performance of basic digital, analog, and mixed-signal circuits employing tunnel-FETs (TFETs). The analysis reviews and complements our previous papers on these topics. By considering the same devices for all the analysis, we are able to draw consistent conclusions for a wide variety of circuits. A virtual complementary TFET technology consisting of III-V heterojunction nanowires is considered. Technology Computer Aided Design (TCAD) models are calibrated against the results of advanced full-quantum simulation tools and then used to generate look-up-tables suited for circuit simulations. The virtual complementary TFET technology is benchmarked against predictive technology models (PTM) of complementary silicon FinFETs for the 10 nm node over a wide range of supply voltages (VDD) in the sub-threshold voltage domain considering the same footprint between the vertical TFETs and the lateral FinFETs and the same static power. In spite of the asymmetry between p- and n-type transistors, the results show clear advantages of TFET technology over FinFET for VDDlower than 0.4 V. Moreover, we highlight how differences in the I-V characteristics of FinFETs and TFETs suggest to adapt the circuit topologies used to implement basic digital and analog blocks with respect to the most common CMOS solutions

Digital and analog TFET circuits: Design and benchmark

In this work, we investigate by means of simulations the performance of basic digital, analog, and mixed-signal circuits employing tunnel-FETs (TFETs). The analysis reviews and complements our previous papers on these topics. By considering the same devices for all the analysis, we are able to draw consistent conclusions for a wide variety of circuits. A virtual complementary TFET technology consisting of III-V heterojunction nanowires is considered. Technology Computer Aided Design (TCAD) models are calibrated against the results of advanced full-quantum simulation tools and then used to generate look-up-tables suited for circuit simulations. The virtual complementary TFET technology is benchmarked against predictive technology models (PTM) of complementary silicon FinFETs for the 10 nm node over a wide range of supply voltages (VDD) in the sub-threshold voltage domain considering the same footprint between the vertical TFETs and the lateral FinFETs and the same static power. In spite of the asymmetry between p- and n-type transistors, the results show clear advantages of TFET technology over FinFET for VDDlower than 0.4 V. Moreover, we highlight how differences in the I-V characteristics of FinFETs and TFETs suggest to adapt the circuit topologies used to implement basic digital and analog blocks with respect to the most common CMOS solutions

Enhanced Hardware Security Using Charge-Based Emerging Device Technology

The emergence of hardware Trojans has largely reshaped the traditional view that the hardware layer can be blindly trusted. Hardware Trojans, which are often in the form of maliciously inserted circuitry, may impact the original design by data leakage or circuit malfunction. Hardware counterfeiting and IP piracy are another two serious issues costing the US economy more than $200 billion annually. A large amount of research and experimentation has been carried out on the design of these primitives based on the currently prevailing CMOS technology. However, the security provided by these primitives comes at the cost of large overheads mostly in terms of area and power consumption. The development of emerging technologies provides hardware security researchers with opportunities to utilize some of the otherwise unusable properties of emerging technologies in security applications. In this dissertation, we will include the security consideration in the overall performance measurements to fully compare the emerging devices with CMOS technology. The first approach is to leverage two emerging devices (Silicon NanoWire and Graphene SymFET) for hardware security applications. Experimental results indicate that emerging device based solutions can provide high level circuit protection with relatively lower performance overhead compared to conventional CMOS counterpart. The second topic is to construct an energy-efficient DPA-resilient block cipher with ultra low-power Tunnel FET. Current-mode logic is adopted as a circuit-level solution to countermeasure differential power analysis attack, which is mostly used in the cryptographic system. The third investigation targets on potential security vulnerability of foundry insider\u27s attack. Split manufacturing is adopted for the protection on radio-frequency (RF) circuit design

Improved parametric analysis of cylindrical surrounding double-gate (CSDG) MOSFET.

Masters Degree. University of KwaZulu-Natal, Durban.Transistors are major components in designing and fabricating high-speed switching devices and micro-electronics. The Metal Oxide Semiconductor Field Effect Transistor (MOSFET) is popular and highly efficient for designing switches. It has wide applications in microelectronics, nanotechnology and Very Large-Scale Integration (VLSI) design where millions of MOSFETs are fabricated and embedded into a single chip. In these applications, heat becomes a major concern and requires to be addressed. The Cylindrical Surrounding Double-Gate (CSDG) MOSFET was introduced to overcome this challenge. The device has two scaled channel paths in a cylindrical two-gate structure, which have excellent control on the electrostatic activities that take place along the channel. This help to reduce corner effect and short channel effect and in turn produce higher drain current. This research work explores these advantages to propose a novel structure for an improved CSDG MOSFET. Firstly, the physical dimensions and structural layout of the improved CDSG MOSFET are highlighted and explained. After that, a parametric analysis of the CDSG MOSFET design has been done. This includes and supported with mathematical analysis and derivation of its operational parameters, namely surface potential, drain current, threshold voltage, transconductance, carrier mobility and capacitive characteristics etc. Thirdly, the thermal effects of this proposed device is analysed at different temperature. Also, the performance of the CDSG MOSFET is analyzed and compared to other existing MOSFET structures. The results from this analysis show that the improved CDSG MOSFET outperforms other existing MOSFETs. In fact, its power consumption is shown to be lower than those of other compared MOSFETs. A practical application of this device as an amplifier also yields plausible performance in terms of amplification gain and efficiency over a wide range of temperatures

Phase Noise Analyses and Measurements in the Hybrid Memristor-CMOS Phase-Locked Loop Design and Devices Beyond Bulk CMOS

Phase-locked loop (PLLs) has been widely used in analog or mixed-signal integrated circuits. Since there is an increasing market for low noise and high speed devices, PLLs are being employed in communications. In this dissertation, we investigated phase noise, tuning range, jitter, and power performances in different architectures of PLL designs. More energy efficient devices such as memristor, graphene, transition metal di-chalcogenide (TMDC) materials and their respective transistors are introduced in the design phase-locked loop. Subsequently, we modeled phase noise of a CMOS phase-locked loop from the superposition of noises from its building blocks which comprises of a voltage-controlled oscillator, loop filter, frequency divider, phase-frequency detector, and the auxiliary input reference clock. Similarly, a linear time-invariant model that has additive noise sources in frequency domain is used to analyze the phase noise. The modeled phase noise results are further compared with the corresponding phase-locked loop designs in different n-well CMOS processes. With the scaling of CMOS technology and the increase of the electrical field, the problem of short channel effects (SCE) has become dominant, which causes decay in subthreshold slope (SS) and positive and negative shifts in the threshold voltages of nMOS and pMOS transistors, respectively. Various devices are proposed to continue extending Moore\u27s law and the roadmap in semiconductor industry. We employed tunnel field effect transistor owing to its better performance in terms of SS, leakage current, power consumption etc. Applying an appropriate bias voltage to the gate-source region of TFET causes the valence band to align with the conduction band and injecting the charge carriers. Similarly, under reverse bias, the two bands are misaligned and there is no injection of carriers. We implemented graphene TFET and MoS2 in PLL design and the results show improvements in phase noise, jitter, tuning range, and frequency of operation. In addition, the power consumption is greatly reduced due to the low supply voltage of tunnel field effect transistor