PLANAR CMOS AND MULTIGATE TRANSISTORS BASED WIDE-BAND OTA BUFFER AMPLIFIERS FOR HEAVY RESISTANCE LOAD

Analog buffer amplifier configurations capable of driving heavy resistive load using different operational transconductance amplifier (OTA) are presented in this paper. The OTA CMOS buffer configurations are designed using 0.18 µm SCL technology library in Cadence Virtuoso tool and multigate transistor OTA buffer in TCAD Sentaurus tool. CMOS OTA buffer configuration using simple OTA outperform the OTA buffer circuits using other OTAs in terms of power dissipation and stability. Measured results show that the OTA buffer circuit works well for resistive load below 100 Ω. The gain tuning of up to 5 V/V is achieved with RL equal to 50 Ω, output swing of 1 V. OTA buffer configuration implemented using multigate transistor with resistive load below 1 kΩ exhibits a bandwidth around 5 GHz and tunable gain up to 5 V/V

Reconfigurable Multifunctional van der Waals Ferroelectric Devices and Logic Circuits

In this work, we demonstrate the suitability of Reconfigurable Ferroelectric Field-Effect- Transistors (Re-FeFET) for designing non-volatile reconfigurable logic-in-memory circuits with multifunctional capabilities. Modulation of the energy landscape within a homojunction of a 2D tungsten diselenide (WSe$_2$) layer is achieved by independently controlling two split-gate electrodes made of a ferroelectric 2D copper indium thiophosphate (CuInP$_2$S$_6$) layer. Controlling the state encoded in the Program Gate enables switching between p, n and ambipolar FeFET operating modes. The transistors exhibit on-off ratios exceeding 10$^6$ and hysteresis windows of up to 10 V width. The homojunction can change from ohmic-like to diode behavior, with a large rectification ratio of 10$^4$. When programmed in the diode mode, the large built-in p-n junction electric field enables efficient separation of photogenerated carriers, making the device attractive for energy harvesting applications. The implementation of the Re-FeFET for reconfigurable logic functions shows how a circuit can be reconfigured to emulate either polymorphic ferroelectric NAND/AND logic-in-memory or electronic XNOR logic with long retention time exceeding 10$^4$ seconds. We also illustrate how a circuit design made of just two Re-FeFETs exhibits high logic expressivity with reconfigurability at runtime to implement several key non-volatile 2-input logic functions. Moreover, the Re-FeFET circuit demonstrates remarkable compactness, with an up to 80% reduction in transistor count compared to standard CMOS design. The 2D van de Waals Re-FeFET devices therefore exhibit groundbreaking potential for both More-than-Moore and beyond-Moore future of electronics, in particular for an energy-efficient implementation of in-memory computing and machine learning hardware, due to their multifunctionality and design compactness.Comment: 23 pages, 5 figures; Supporting Information: 12 pages, 6 figure

Data Conversion Within Energy Constrained Environments

Within scientific research, engineering, and consumer electronics, there is a multitude of new discrete sensor-interfaced devices. Maintaining high accuracy in signal quantization while staying within the strict power-budget of these devices is a very challenging problem. Traditional paths to solving this problem include researching more energy-efficient digital topologies as well as digital scaling.;This work offers an alternative path to lower-energy expenditure in the quantization stage --- content-dependent sampling of a signal. Instead of sampling at a constant rate, this work explores techniques which allow sampling based upon features of the signal itself through the use of application-dependent analog processing. This work presents an asynchronous sampling paradigm, based off the use of floating-gate-enabled analog circuitry. The basis of this work is developed through the mathematical models necessary for asynchronous sampling, as well the SPICE-compatible models necessary for simulating floating-gate enabled analog circuitry. These base techniques and circuitry are then extended to systems and applications utilizing novel analog-to-digital converter topologies capable of leveraging the non-constant sampling rates for significant sample and power savings

Frontiers in microphotonics: tunability and all-optical control

The miniaturization of optical devices and their integration for creating adaptive and reconfigurable photonic integrated circuits requires effective platforms and methods to control light over very short distances. We present here several techniques an