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With more than thirty years of research and development until commercialization, performance, reliability, and robustness of silicon carbide (SiC) based devices have been improved significantly due to drastic reduction in crystal defects from the well-controlled processes of crystal growth and device fabrication. It is crucial to investigate the effects of SiC crystal defects on the electrical characteristics of devices. Here, an up-to-date development of the correlation between crystal defects of SiC with electrical performance of the devices has been reviewed. The effect of defects on the electrical parameters of the device and the failure mechanism are discussed, and the development of SiC in recent years is prospected. [ABSTRACT FROM AUTHOR] more...

Resistive switching is a promising technology for artificial synapses, the most critical component and building block of a neural network for brain-inspired neuromorphic computing. The artificial synapse is capable of emulating a signal process and memory functions of biological synapses. The artificial synapse fabricated by natural bioorganic materials is essential for developing soft, flexible, and biocompatible electronics and sustainable, biodegradable, and environmentally friendly neuromorphic systems. In this work, a natural biomaterial—honey based resistive switching device—was demonstrated to emulate some important functionalities of biological synapses, including synaptic potentiation and depression, short-term and long-term memory, spatial summation, and shunting inhibition. The results indicate the potential of honey based resistive switching for artificial synaptic devices in renewable neuromorphic systems and bioelectronics. [ABSTRACT FROM AUTHOR] more...

In this paper, we report resistive random access memory (RRAM) based on a monosaccharide—fructose for nonvolatile memory in biocompatible and "green" electronics. Fructose thin film acts as the resistive switching layer with Al and Ag top electrodes for comparison. Both devices demonstrated highly reproducible nonvolatile bipolar resistive switching behaviors with a large on/off ratio of ∼106 for the Al electrode and ∼105 for the Ag electrode. The forming voltage, set voltage, and memory window are also larger for the Al electrode than the Ag electrode, but the reset voltages are comparable. Dominant conduction mechanisms of fructose films were proposed. At a high resistance state, both electrodes reveal space charge limited conduction, while at a low resistance state, the governing mechanism is Ohm's law, and in addition, the Ag electrode also shows trap-fill limited conduction when approaching the reset voltage. This observation has yet to be reported in RRAM based on natural bio-organic materials. [ABSTRACT FROM AUTHOR] more...

A systematic electrical and physical characterization of gate oxides on 4H-SiC, grown in diluted N[sub 2]O at 1300 °C, has been performed. Electrical characterization by the high-frequency C-V technique, conductance technique, and slow trap profiling method reveals that the densities of interface and near-interface traps, and the effective oxide charge for gate oxides grown in 10% N[sub 2]O are the lowest, compared to gate oxides grown in 100% and 0.5% N[sub 2]O. These results are supported by physical characterizations using x-ray photoelectron spectroscopy, secondary ion mass spectroscopy, and atomic force microscopy. It has been shown that carbon clusters, accumulated at the SiC-SiO[sub 2] interface, directly influence the roughness of the interface and the densities of the interface and near-interface traps. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR] more...

Current conduction mechanisms of an atomic-layer-deposited Al2O3 gate on n-type 4H SiC have been systematically investigated, analyzed, and reported in this letter. It has been revealed that space charge limited, Poole-Frenkel (PF) emission, combination of PF emission and Fowler-Nordheim tunneling are the dominate current conduction mechanisms in the dielectric. Besides, Schottky emission has also been proposed as a possible leakage path at temperature beyond the investigated range. A relationship among the conduction mechanism, temperature, and applied electric field has been presented. [ABSTRACT FROM AUTHOR] more...

The effects of thermal nitrided gate-oxide thickness on n-type 4H silicon-carbide-based metal-oxide-semiconductor characteristics have been reported. Seven different thicknesses of oxide (tox), ranging from 2 to 20 nm, have been investigated. It has been shown that effective oxide charge (Qeff) and total interface-trap density (Nit) have demonstrated a cyclic trend as tox is increased. These observations have been explained in the letter. Correlations of Qeff and Nit with oxide breakdown field and current transport mechanism in these oxides have also been established and explained. [ABSTRACT FROM AUTHOR] more...

In this letter, the possibility of using metal-oxide-semiconductor capacitors on SiC as nonvolatile random-access memory elements has been experimentally investigated. Because of the wide energy gap and the very low minority-carrier generation rate in SiC, it should be possible to achieve very long retention times. The investigations show that charge leakage through the gate oxide may prevent the use of SiC metal-oxide-semiconductor (MOS) capacitors as memory elements. Importantly, the experiments demonstrate that both the charge leakage and carrier-generation rate are low in the case of nitrided SiO[sub 2]-SiC interfaces. The retention time extrapolated to room temperature is in the order of 10[sup 9] years for the case of MOS capacitors on 4H-SiC, which is approximately equal to the theoretical limit. [ABSTRACT FROM AUTHOR] more...