Development of an Electrothermal Simulation Tool for Integrated Circuits

The goal of this research was to develop a capability for the electrothermal modeling of electronic circuits. The objective of the thermal modeling process was to create a model that represents the thermal behavior of the physical system. The project focuses on electrothermal analysis at devices and chip level. A novel method to perform electrothermal analysis of integrated circuits based on the relaxation approach is proposed in this research. An interface program couples a circuit simulator and a thermal simulator. The developed simulator is capable of performing both steady state and transient analaysis at devices and chip level. The proposed method was applied to perform electrothermal analysis of Silicon Bipolar Junction Transistor (BJT) to predict the temperature distribution and the device performance in a circuit. Thermal nonlinearity due to temperature-dependent material parameters in the context of thermal modeling of the device and circuit has also been considered. The DC characteristics of the device were investigated. The obtained results indicate that the operating point of the device varies while the device reaches its junction temperature. The accuracy of the electrothermal simulator has been evaluated for steady state analysis. The experimental results of a BJT amplifier were compared to the simulator results of the similar circuit. The electrothermal simulation results of BJT amplifier circuit indicate a good agreement with the available experimental results in terms of power dissipation, collector current and base-emitter voltage. The performance of the electrothermal simulator has been evaluated for tansient analysis. A current mirror circuit using Si NPN BJTs was simulated. According to the electrical simulator, the output current follows the reference current immediately. Nonetheless, the electrothermal simulator results depict that the load current has delay to reach a constant value which is not the same as the reference current, due to the influence of thermal coupling and self heating. The obtained results are in agreement with the available results in literature.

Development of an Electrothermal Simulation Tool for Integrated Circuits

The goal of this research was to develop a capability for the electrothermal modeling of electronic circuits. The objective of the thermal modeling process was to create a model that represents the thermal behavior of the physical system. The project focuses on electrothermal analysis at devices and chip level. A novel method to perform electrothermal analysis of integrated circuits based on the relaxation approach is proposed in this research. An interface program couples a circuit simulator and a thermal simulator. The developed simulator is capable of performing both steady state and transient analaysis at devices and chip level. The proposed method was applied to perform electrothermal analysis of Silicon Bipolar Junction Transistor (BJT) to predict the temperature distribution and the device performance in a circuit. Thermal nonlinearity due to temperature-dependent material parameters in the context of thermal modeling of the device and circuit has also been considered. The DC characteristics of the device were investigated. The obtained results indicate that the operating point of the device varies while the device reaches its junction temperature. The accuracy of the electrothermal simulator has been evaluated for steady state analysis. The experimental results of a BJT amplifier were compared to the simulator results of the similar circuit. The electrothermal simulation results of BJT amplifier circuit indicate a good agreement with the available experimental results in terms of power dissipation, collector current and base-emitter voltage. The performance of the electrothermal simulator has been evaluated for tansient analysis. A current mirror circuit using Si NPN BJTs was simulated. According to the electrical simulator, the output current follows the reference current immediately. Nonetheless, the electrothermal simulator results depict that the load current has delay to reach a constant value which is not the same as the reference current, due to the influence of thermal coupling and self heating. The obtained results are in agreement with the available results in literature.

Circuit-Based Electrothermal Simulation of Multicellular SiC Power MOSFETs Using FANTASTIC

This paper discusses the benefits of an advanced highly-efficient approach to static and dynamic electrothermal simulations of multicellular silicon carbide (SiC) power MOSFETs. The strategy is based on a fully circuital representation of the device, which is discretized into an assigned number of individual cells, high enough to analyze temperature and current nonuniformities over the active area. The cells are described with subcircuits implementing a simple transistor model that accounts for the utmost influence of the traps at the SiC/SiO2 interface. The power-temperature feedback is emulated with an equivalent network corresponding to a compact thermal model automatically generated by the FANTASTIC tool from an accurate 3D mesh of the component under test. The resulting macrocircuit can be solved by any SPICE-like simulation program with low computational burden and rare occurrence of convergence issues.

Compact electrothermal model of laboratory made GaN Schottky diodes

Purpose The purpose of this paper is to propose a simple electrothermal model of GaN Schottky diodes, and its usefulness for circuit-level electrothermal simulation of laboratory-made devices is proved. Design/methodology/approach The compact electrothermal model of this device has the form of a subcircuit for simulation program with integrated circuit emphasis. This model takes into account influence of a change in ambient temperature in a wide range as well as influence of self-heating phenomena on dc characteristics of laboratory-made GaN Schottky diodes. The method of model parameters estimation is described. Findings It is shown that temperature influences fewer characteristics of GaN Schottky diodes than classical silicon diodes. The discussed model accurately describes properties of laboratory made GaN Schottky diodes. Additionally, the measured and computed characteristics of these diodes are shown and discussed. Research limitations/implications The presented model together with the results of measurements and computations is dedicated only to laboratory-made GaN Schottky diodes. Originality/value The presented investigations show that characteristics of laboratory-made GaN Schottky diodes visibly change with temperature. These changes can be correctly estimated using the compact electrothermal model proposed in this paper. The correctness of this model is proved for four structures of such diodes characterised by different values of structure area and a different assembly process.