Mitiko Miura-Mattausch

The hot‐electron problem in small semiconductor devices

Decreasing device dimensions will cause an increasing internal field strength in a semiconductor device. The average carrier energy is different from the thermal equilibrium value 3/2 kT. Modification of current transport is considered on different levels of approximation. In a local approximation we derive a field‐dependent carrier mobility and temperature from a more general self‐consistent formulation. Numerical estimation of hot‐electron effects are given for a realistic n‐channel metal‐oxide‐semiconductor field‐effect transistor of various channel lengths. It is shown that both high‐field and field‐gradient effects will contribute.

HiSIM2: Advanced MOSFET Model Valid for RF Circuit Simulation

The compact MOSFET model development trend leads to models based on the channel surface potential, allowing higher accuracy and a reduced number of model parameters. Among these, the Hiroshima University Semiconductor Technology Academic Research Center IGFET Model (HiSIM) solves the surface potentials with an efficient physically correct iteration procedure, thus avoiding additional approximations without any computer run-time penalty. It is further demonstrated that excellent model accuracy for higher-order phenomena, which is a prerequisite for accurate RF circuit simulation, is achieved by HiSIM without any new model parameters in addition to those for describing the current-voltage characteristics

Completely Surface-Potential-Based Compact Model of the Fully Depleted SOI-MOSFET Including Short-Channel Effects

The reported circuit simulation model Hiroshima University semiconductor technology academic research center IGFET model silicon-on-insulator (HiSIM-SOI) for the fully depleted SOI-MOSFET is based on a complete surface-potential description. Not only the surface potential in the MOSFET channel, but also the potentials at both surfaces of the buried oxide are solved iteratively, which allows including of all relevant device features of the SOI-MOSFET explicitly and in a physically correct way. In particular, an additional parasitic electric field, induced by the surface-potential distribution at the buried oxide, has to be included for accurate modeling of the short-channel effects. The total iteration time for surface potential calculation with HiSIM-SOI is under most bias conditions only a factor 2.0 (up to a factor 3.0 for some bias conditions) longer than for the bulk-MOSFET HiSIM model, where just the channel surface potential is involved. It is verified that HiSIM-SOI reproduces measured current-voltage (I-V) and 1/f noise characteristics of a 250-nm fully depleted SOI technology in the complete operating range with an average error of 1% and 15%, respectively. Stable convergence of HiSIM-SOI in the circuit simulation is confirmed

The physics and modeling of MOSFETS : surface-potential model HiSIM

Semiconductor Device Physics Basic Compact Surface-Potential Model of the MOSFET Advanced MOSFET Phenomena Modeling Capacitances Noise Models Non-Quasi-Static (NQS) Model Leakage Currents Source/Bulk and Drain/Bulk Diode Models Source/Drain Resistances Effects of the Source/Drain Diffusion Length for Shallow Trench Isolation (STI) Technologies Summary of Model Equations Exclusion of Modeled Effects and Model Flags.

A Carrier-Transit-Delay-Based Nonquasi-Static MOSFET Model for Circuit Simulation and Its Application to Harmonic Distortion Analysis

In this paper, a compact model of nonquasi-static (NQS) carrier-transport effects in MOSFETs is reported, which takes into account the carrier-response delay to form the channel. The NQS model, as implemented in the surface-potential-based MOSFET Hiroshima University STARC IGFET model, is verified to predict the correct transient terminal currents and to achieve a stable circuit simulation. Simulation results show that the NQS model can even reduce the circuit simulation time in some cases due to the elimination of unphysical overshoot peaks normally calculated by a QS-model. An average additional computational cost of only 3% is demonstrated for common test circuits. Furthermore, harmonic distortion characteristics are investigated using the developed NQS model. While the distortion characteristics at low drain bias and low switching frequency are determined mainly by carrier mobility, distortion characteristics at high frequency are found to be strongly influenced by channel charging/discharging

HiSIM-HV: A Compact Model for Simulation of High-Voltage MOSFET Circuits

The completely surface-potential-based MOSFET model HiSIM-HV for high-voltage applications of up to several hundred volts is reviewed, and recently developed new model capabilities are presented. HiSIM-HV enables a consistent evaluation of current and capacitance characteristics for symmetric and asymmetric high-voltage MOSFETs due to a consistent description of the potential distribution across the MOSFET channel as well as the resistive drift regions. The anomalous features, often observed in the capacitances, are explained by large potential drops in the drift regions. Accurate modeling of the overlap region between the gate and drift region is also demonstrated. Different device features based on different device structures are well explained by the geometrical differences.

Universal NBTI Compact Model for Circuit Aging Simulation under Any Stress Conditions

In this paper, a compact model for the negative bias temperature instability (NBTI) is developed by considering the interface-state generation and the hole-trapping mechanisms. This model shows accurate reproduction of the threshold voltage (Vth) degradations measured from samples fabricated with different dielectric materials as well as processes. A total of eight model parameters are introduced for describing the different degradation origins. The parameter values are verified to exhibit universal properties as a function of the electrical field within the gate oxide (Eox). By implementing the universal NBTI model into the compact model HiSIM, the dynamic NBTI effect and circuit performance degradation can be predicted.

HiSIM: a drift-diffusion-based advanced MOSFET model for circuit simulation with easy parameter extraction

We present here the MOSFET model HiSIM (Hiroshima University Starc IGFET model). As HiSIM employs the drift-diffusion approximation and preserves correct modeling of the surface potential in the channel, it is not only accurate, but additionally, model parameter number is small, parameter interdependence is removed, and parameter extraction becomes easy. Measured current-voltage characteristics of advanced MOSFETs are thus reproduced with only 19 model parameters.

Physical modeling of the reverse-short-channel effect for circuit simulation

The proposed threshold-voltage (V/sub th/) model for circuit simulation includes reverse-short-channel effects (RSCE) and short-channel effects (SCE) based on their respective physical origins. A linear vertical-impurity profile approximation for simplified RSCE-modeling already enables 8 mV average V/sub th/-accuracy (max<45 mV) under all bias conditions for source, drain, and bulk for L/sub gate/ down to 0.15 /spl mu/m. The complete V/sub th/-model needs only ten constant L/sub gate/-independent parameters.

Analytical Model for Circuit Simulation with Quarter Micron Metal Oxide Semiconductor Field Effect Transistors : Subthreshold Characteristics

For deep submicron MOSFETs short-channel effects dominate the transistor characteristics. This is due to the increase of the lateral electric field. This paper provides a new simple model which includes the gradient of the lateral electric field in an analytical way. The model describes the subthreshold characteristics relating to short-channel effects correctly down to 0.1 µm effective channel length Leff with physical parameters (Nsub, Cox, Vfb, f) taken from the long-channel device.