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Analytical expression for the 3-D potential distributions along the channel of lightly doped silicon trigate MOSFETs is derived and compared with 3-D Poisson's equation. Results show the possibility of obtaining 30-nm channel length in silicon TG MOSFETs and subthreshold slope of ideal value 60mV/dec at 300K.

A simple analytical two-dimensional (2-D) model is derived for the threshold voltage of undoped symmetrical double-gate (DG) MOSFET, which is based on an analytical solution of the 2-D Poisson's equation for the potential distribution. Good agreement is achieved between the model and the simulation results by calibrating the minimum carrier charge sheet density adequate to achieve the turn-on condition.

The derivation of a simple analytical expression of the 2-D potential distribution along the channel of silicon sub-30-nm symmetrical double-gate MOSFETs (DG MOSFETs) is discussed. Findings reveal that the analytical expression is useful in accurate description of the potential distribution along the channel at different positions from the gate interfaces for well-designed devices.

An experimental and theoretical investigation of memory-cell structures that use either natural nitride traps or semiconductor nano-crystals is proposed. Charging/discharging phenomena are examined, and an interpretation of experimental results is presented.

Research was conducted to examine charge transport through interpoly thin nitride/oxide stacked films including nitride/oxide dual- and oxide/nitride/oxide tri-layer films. The transport mechanisms of stacked interpoly dielectrics were investigated starting from single-layer conduction analysis. A consistent two-step trap-assisted model is proposed for the nitric oxide structure.

In this work we have investigated how gamma irradiation affects the tunneling conduction mechanism of a 20 nm thick oxide in MOS capacitors. The radiation induced positive charge is rapidly compensated by the injected electrons, and does not impact the gate current under positive injection after the first current-voltage measurement. Only a transient stress induced leakage current at low gate bias is observed. Instead, a radiation induced negative charge has been observed near the polysilicon gate, which enhances the gate voltage needed for Fowler-Nordheim conduction at negative gate bias. No time decay of this charge has been observed. Such charges slightly modify the trapping kinetics of negative charge during subsequent electrical stresses performed at constant current condition.

MOS capacitors with a 4.4 nm thick gate oxide have been exposed to [Gamma] radiation from a [Co.sup.60] source. As a result, we have measured a stable leakage current at fields lower than those required for Fowler-Nordheim tunneling. This Radiation Induced Leakage Current (RILC) is similar to the usual Stress Induced Leakage Currents (SILC) observed after electrical stresses of MOS devices. We have verified that these two currents share the same dependence on the oxide field, and the RILC contribution can be normalized to an equivalent injected charge for Constant Current Stresses. We have also considered the dependence of the RILC from the cumulative radiation dose, and from the applied bias during irradiation, suggesting a correlation between RILC and the distribution of trapped holes and neutral levels in the oxide layer.

A generalized trapping kinetic model with appropriate trap cross-section and density profiles for the power law degradation observed in thin dielectrics after Fowler-Nordheim is proposed. A mathematical analysis of the negative bulk oxide charge kinetics has been established using incomplete Gamma and generalized hypergeometric functions after assuming exponentially varying trap cross-section and density profiles throughout the oxide. The model provides very good fitting of the variation of the trapped oxide charge with the injection dose for oxide thicknesses between 5.5 and 10 nm.

A quantitative analysis was performed on the influence of oxide quality on the endurance characteristics of electrically erasable programmable read only memories (EEPROM). Results showed that bulk oxide charges present in tunnel oxides of EEPROM cells and capacitors were caused by a charge generation process independent of the stress mode. This phenomena was used as a basis for the proposal of a criterion applicable to optimizing tunnel oxide technology which would produce high endurance nonvolatile memory structures.

The physical bases of the most commonly used methods for the one-dimensional calculation of direct-tunneling current in metal–oxide–semiconductor (MOS) structures (i.e., Bardeen’s approach, the resonant transfer matrix method, and transparency-based approximations) are discussed. Each of them is presented in detail, underlining in a simple way the basic principles. In particular, an original derivation for Bardeen’s approach is proposed. A comparison of the different methods is then carried out for the simple case of two square quantum wells, where analytical solutions can be given, and for actual MOS structures, taking into account quantization effects. It is shown that all these methods, despite the very different formalisms, are based on similar physical approaches and provide very close results. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The 'dummy cell' is insignificant in the novel technique that yields drain coupling ratios and control gate ratios directly on FLOTOX EEPROM cells. The write pulses' hold time determines the high state threshold voltage and forms the basis of the new technique. Speed, precision and simplicity are the benefits of the proposed new scheme, which involves the sensitivity of coupling ratios to effective values.

The endurance performance of FLOTOX EEPROM cells, which is influenced by the RIE process step, is performed with O2 + CHF3 plasma and analyzed. The thickness of the tunnel oxide is increased by the fluorine contamination introduced in the SIO2. The endurance performance of FLOTOX EEPROM cells is adequately recovered by optimized post-RIE annealing. The degradation qualities of the cells that were subjected to the RIE process were studied after being compared with the Wet Etching Procedure (WEP).

An approach giving a physical understanding of the stress-induced leakage current (SILC) generation kinetic based on anode hole injection and hole dispersive transport in the oxide is present. It is shown that the SILC is not directly correlated to the defects responsible for oxide breakdown.