1,721,338 research outputs found
On the Modeling of Surface Roughness Limited Mobility in SOI MOSFETs and its Correlation to the Transistor Effective Field
No full textOn the origin of the dispersion of erased threshold voltages in flash eeprom memory cells
No full textExperimental Signature and Physical Mechanisms of Substrate Enhanced Gate Current in MOS Devices
No full textThis paper examines in detail the phenomenon of Substrate Enhanced Electron Injection (SEEI). By using floating gate devices less aggressively scaled than the MOSFETs of Bude (1995) we are able to: (1) develop criteria to separate SEEI from the coexisting channel hot electron (CHE) injection; (2) point out a direct proportionality between the gate (I/sub G/) and the substrate (I/sub B/) currents that provides a signature of SEEI; (3) reconcile SEEI with reported mechanisms of optical minority carrier generation in the substrate
"A Better Understanding of Substrate Enhanced Gate Current in VLSI MOSFET's and Flash Cells - Part II: Physical Analysis
No full textIn this work different physical mechanisms that could lead to the direct proportionality between la and IB highlighted in Part I as the signature of substrate enhanced electron injection (SEEI), are analyzed in detail. By means of experiments and simulations we substantiate the current interpretation of SEEI in terms of an impact ionization feedback process and attribute a quantitatively negligible role to both drain avalanche hot electron injection and substrate electrons generated by the photons emitted by channel hot electrons. These experiments reconcile the current explanation of SEEI with the well known phenomenon of photon assisted minority carrier injection in the substrate, whose presence is clearly detectable in our devices, but whose impact on the gate current is estimated to be orders of magnitude smaller than that of impact ionization feedback
"A Better Understanding of Substrate Enhanced Gate Current in VLSI MOSFET's and Flash Cells - Part I: Phenomenological Aspects"
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Linear combination of bulk bands method for investigating the low-dimensional electron gas in nanostructured devices
No full textThis paper concerns the determination of the band structure of physical systems with reduced dimensionality with the method of the linear combination of bulk band (LCBB), according to the full-band energy dispersion of the underlying crystal. The derivation of the eigenvalue equation is reconsidered in detail for quasi-two-dimensional (2D) and quasi-one-dimensional (1D) systems and we demonstrate how the choice of the volume expansion in the three-dimensional reciprocal lattice space is important in order to obtain a separated eigenvalue problem for each wave vector in the unconstrained plane (for 2D systems) or in the unconstrained direction (for 1D systems). The clarification of the expansion volume naturally leads to identification of the 2D and 1D first Brillouin zone (BZ) for any quantization direction. We then apply the LCBB approach to the silicon and germanium inversion layers and illustrate the main features of the energy dispersion and the 2D first BZ for the [001], [110], and [111] quantization directions. We further compare the LCBB energy dispersion with the one obtained with the conventional effective mass approximation (EMA) in the case of (001) silicon inversion layers. As an interesting result, we show that the LCBB method reveals a valley at the edge of the 2D first BZ which is not considered by the EMA model and that gives a significant contribution to the 2D density of states
BipFLASH: a Novel Non-Volatile Memory Cell Concept for High Speed - Low Power Applications
No full textWe present a novel non-volatile memory cell architecture, which remarkably improves injection efficiency overconventional channel hot electron programming. We show how this superior performance can be traded to achieve either lowvoltage-low power or high-speed operation. The cell concept is validated by means of numerical device simulations. Criteriafor device optimization are also discussed
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