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Eric M. Vogel - IEEE Xplore Author Profile

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Micromodular n-channel metal-oxide-silicon transistors were fabricated, transferred to a foreign substrate, and adaptively interconnected using high-resolution electrohydrodynamic jet (e-jet) printed metal wires to create depletion-load nMOS inverters. The transferred transistors have effective electron mobilities approaching 500 cm $^{{2}} \cdot $ V $^{-{1}} \cdot $ s−1 and subthreshold swing a...Show More
In this article, we propose an electrical bias technique to recover the accuracy of a degraded ${\text {HfO}}_{x}$ -based resistive random access memory (ReRAM) array in deep neural network (DNN) training. We simulate degradation through the application of ${\sim } {10}^{{4}}$ pulses having high pulse amplitude, resulting in a fatigued ReRAM array that fails to converge during training. We prop...Show More
Neural networks utilizing non-volatile random access memory (NVM) exhibit excellent power reduction over traditional CMOS implementations. RRAM (resistive random access memory) is one such emerging memory technology offering low energy, good endurance, and a large analog conductance window. When implemented in a crossbar architecture, these networks are able to bypass the von-Neumann bottleneck by...Show More
Field effect transistors (FETs) with their Boolean operation have been the fundamental building block of digital computers. While this digital framework is excellent at performing complex arithmetic and logic calculations, it lags far behind the human brain in key areas such as adaptivity, generalization, and pattern recognition. Neuromorphic computation using nanoscale adaptive oxide devices or m...Show More
Tunneling-dominated charge transport is demonstrated in vertically stacked MoS2/interlayer/MoS2 heterostructures with Al2O3, hexagonal boron nitride (h-BN), and HfO2 dielectrics. All devices are highly resistant to 10-keV X-ray irradiation. Only small transient changes in X-ray-induced photocurrent are observed as a result of trap creation in the thin interlayer dielectric, with rapid passivation....Show More
We have performed a detailed evaluation of radiation-induced charge trapping and low-frequency noise for back-gated graphene transistors fabricated on a thermal SiO2 layer, with Al2O3 or hexagonal boron nitride passivation over-layers. Irradiation with positive or 0 V back-gate bias leads to negative shifts of the charge neutral point (CNP) of the graphene transistors; irradiation under negative b...Show More
Strong enhancement of Raman signal upon integration of trilayer MoS2 with Fabry-Perot (FP) optical cavities is reported. We also discuss prospective application of enhanced light matter interaction in 2D materials for energy harvesting purposes.Show More
High-mobility alternative channel materials to silicon are critical to the continued scaling of MOS devices. The analysis of capacitance–voltage (C–V) measurements on these new materials with high-k gate dielectrics is a critical technique to determine many important gate-stack parameters. While there are very useful C–V analysis tools available to the community, these tools are all limited in the...Show More
Spiking neural circuits have been designed in which the memristive synapses exhibit spike timing-dependent plasticity (STDP). STDP is a learning mechanism where synaptic weight (the strength of the connection between two neurons) depends on the timing of pre-and post-synaptic action potentials. A known capability of networks with STDP is detection of simultaneously recurring patterns within the po...Show More
Aggressive scaling of logic devices is quickly approaching the physical limitations of conventional CMOS devices, resulting in the need for novel device architectures. One proposed device is the 2-D interlayer tunnel field-effect transistor (ITFET), which relies on tunneling within a vertical heterostructure of 2-D materials. Steep-slope operation of the ITFET relies on proper band alignment for t...Show More
We demonstrate piezoresistive strain sensors based on flexible MoS2 field-effect transistors made from a highly uniform large-area trilayer film. The origin of the piezoresistive effect in MoS2 is explained to be a strain-induced band gap change, as confirmed by optical spectroscopy. The results are in good agreement with recently reported simulations and spectroscopic studies on strained exfoliat...Show More
Molybdenum disulfide (MoS2) has recently received significant attention because of its interesting thickness-dependent properties and its potential as a semiconducting substitute to graphene [1,2]. Most of the studies so far have focused on small (< 100 microns) exfoliated MoS2 flakes [1-3]. For manufacturable electronics, it is essential to have large-area material that is compatible with standar...Show More
Forming-free resistive memories (RRAM) have recently attracted significant attention as the forming process requires high voltage and can lead to low yield because of current overshoot [1-2]. We have recently demonstrated forming-free switching with multi-level operation in TiN/HfTiOx/TiN resistive memories [3]. However, a fundamental understanding of the switching mechanisms is lacking. Recently ...Show More
A high-performance resistive random access memory with graphene top and bottom electrodes and TiOx/Al2O3/TiO2 dielectric stacks is reported. The devices exhibit forming-free switching with stable operation at sub-μA operating current. The switching is highly nonlinear with rectifying characteristics in the sub-μA regime. As a result, the reset current is orders of magnitude smaller than the curren...Show More
Graphene as a conducting electrode has attracted significant attention due to its low sheet resistance, high flexibility and high transparency [1]. Recently, high out-of-plane resistance of graphene has been utilized to reduce the operating current in metal oxide based resistive memories (RRAMs) [2]. However, this report also indicates that the high out-of-plane resistance of graphene contributes ...Show More
The random telegraph noise (RTN) related read instability in resistive random access memory (RRAM) is evaluated by employing the RTN peak-to-peak (P-p) amplitude as a figure of merit (FoM). Variation of the FoM value over multiple set/reset cycles is found to follow the log-normal distribution. P-p decreases with the reduction of the read current, which allows scaling of the RRAM operating current...Show More
We report multilevel switching in forming-free resistive random access memories (RRAMs) with atomic layer deposited HfTiOx nanolaminate (5 nm) as the dielectric. The devices are fabricated using materials and processes compatible with complementary metal-oxide-semiconductor fabrication, including atomic layer deposition for the mixed dielectric structure. The devices switch between ON/OFF states a...Show More
Spiking neuron circuits consisting of ambipolar nanocrystalline-silicon (nc-Si) thin-film transistors (TFTs) have been fabricated using low temperature processing conditions (maximum of 250 °C) that allow the use of flexible substrates. These circuits display behaviors commonly observed in biological neurons such as millisecond spike duration, nonlinear frequency-current relationship, and spike fr...Show More
Spike-timing-dependent plasticity (STDP) is a fundamental learning rule observed in biological synapses that is desirable to replicate in neuromorphic electronic systems. Nanocrystalline-silicon thin film transistors (TFTs) and memristors can be fabricated at low temperatures, and are suitable for use in such systems because of their potential for high density, 3-D integration. In this paper, a co...Show More
We introduce a figure of merit (FoM) to quantify RRAM read current instability, a complex multi-level RTN-like signal, generally observed in read current. Log(FoM) follows a normal statistical distribution describing the probability of occurrence of a read current fluctuation of a given amplitude. We demonstrate that peak-to-peak RTN amplitude decreases with the reduction of the read current that ...Show More
Affinity-based biological sensor field-effect transistors (BioFETs) exhibit a large amount of noise in their drain current under constant bias. In this work, we use SPICE to simulate the effect of sensor noise on a differential pair amplifier detection circuit. This is accomplished by the generation of a realistic noise signal with 1/f power spectrum which is applied to the back gate and reference...Show More
Contact resistance (Rc) contributes over 65% of the total source to drain series resistance in <; 32 nm CMOS technologies. In this work, reduction of Rc is achieved by lowering the SBH through the incorporation of new materials into NiPtSi. The impact of implanted elemental species as well as alloyed low work function metals is discussed. As diffusion and subsequent interface composition is highly...Show More
Properties of neural circuits are demonstrated via SPICE simulations and their applications are discussed. The neuron and synapse subcircuits include ambipolar nano-crystalline silicon transistor and memristor device models based on measured data. Neuron circuit characteristics and the Hebbian synaptic learning rule are shown to be similar to biology. Changes in the average firing rate learning ru...Show More
Silicon-on-insulator (SOI) field-effect-based sensors are often biased using a back substrate gate with biological/electrolytic solutions placed over the top sensor channel. For electrically floating electrolytes in contact with the SOI-buried oxide, we demonstrate that the electrolyte voltage is capacitively coupled to the applied back-gate bias resulting in a dual-gated sensor. Measured electrol...Show More