Marian Molnar

Fast 3-D Electrothermal Device/Circuit Simulation of Power Superjunction MOSFET Based on SDevice and HSPICE Interaction

Automated interaction of SDevice and HSPICE for fast 3-D electrothermal simulation based on the relaxation method is designed. The results are compared with device finite element model simulation and a direct method with an equivalent thermal 3-D RC network. The features and limitations of the methods are analyzed and presented. The designed electrothermal simulation based on the relaxation method is developed for Synopsys TCAD Sentaurus environment for decreasing the simulation time for complex 3-D devices. A power vertical superjunction MOSFET under an unclamped inductive switching test of device robustness is used to perform validation of the designed electrothermal simulation.

Advanced Methodology for Fast 3-D TCAD Device/Circuit Electrothermal Simulation and Analysis of Power HEMTs

This paper introduces an advanced methodology for fast 3-D Technology Computer Aided Design (TCAD) electrothermal simulation for the analysis of power devices. The proposed methodology is based on coupling finite element method (FEM) thermal and circuit electrical simulation in a mixed-mode setup. A power InAlN/GaN high-electron mobility transistor (HEMT) is used to perform validation of the designed electrothermal simulation. A new equivalent temperature-dependent nonlinear analytical large signal circuit model of HEMT is proposed. The model is implemented to Synopsys TCAD Sentaurus using compact model interface. The designed electrothermal simulation methodology is developed to shorten the simulation time for complex 3-D devices. This approach combines the speed and accuracy, and couples temperature nonuniformity to the active device electrothermal behavior. The simulation results are compared with the measured data and results of 2-D FEM simulations. The features and limitations of the methods are analyzed and presented.

Self-Heating in GaN Transistors Designed for High-Power Operation

DC and transient self-heating effects are investigated in normally off AlGaN/GaN transistors designed for a high-power operation. Electrical and optical methods are combined with thermal simulations; 2-μs-long voltage pulses dissipating about 4.5 W/mm are applied on four different transistor structures combining GaN or AlGaN buffer on an n-type SiC substrate with or without Ar implantation. Transistors with only 5% Al mass fraction in the buffer show almost a threefold increase in the transient self-heating if compared with devices on the GaN buffer. On the other hand, 2-μs-long pulses were found not to be long enough for the Ar-implanted SiC substrate to influence the device self-heating unless AlGaN composition changes. In the dc mode, however, both the buffer composition and Ar implantation significantly influence the self-heating effect with the highest temperature rise for the transistor having the AlGaN buffer grown on the Ar-implanted SiC. We point on possible tradeoffs between the transistor high-power design and the device thermal resistance.

Advanced methodology for fast 3-D TCAD electrothermal simulation of power HEMTs including package

This paper introduces an advanced methodology for fast 3-D TCAD electrothermal simulation for the analysis of complex power devices including package and cooling assemblies. The proposed methodology is based on coupling a 3-D finite element method (FEM) thermal model of the package, 3-D FEM electrical model of the metallization layers and circuit electrical model using a mixed-mode setup in Synopsys TCAD Sentaurus environment. This approach combines the speed and accuracy, and couples temperature and current density nonuniformity in structure and metallization layers. A power InAlN/GaN high-electron mobility transistor (HEMT) is used to perform validation of the designed electrothermal simulation. The simulation results are compared with measured data and 2/3-D FEM simulations. The low time consuming simulation approach helps to optimize more complex power structures and systems including all main fabrication parameters from semiconductor layers, metallization, package, and up to cooling assemblies.

Electro-thermal analysis and optimization of edge termination of power diode supported by 2D numerical modeling and simulation

Abstract High reliability and performance of power semiconductor devices depend on an optimized design based on a good understanding of their electro-thermal behavior and of the influence of parasitic components on their operation. This leads to the need for electro-thermal 2/3-D numerical modeling and simulation in power electronics as an efficient tool for analysis and optimization of device structure design and identification of critical regions. In this paper we present an analysis and geometry optimization of a high power pin diode structure supported by advanced 2-D mixed mode electro-thermal device and circuit simulation. Lowering of the operation temperature by better power management and heat dissipation due to an optimized structure design will allow withstanding higher current pulses and suppressing the damage of the analyzed structure by thermal breakdown.

Analysis of reliability and optimization of ESD protection devices supported by modeling and simulation

Abstract An analysis of electrostatic discharge (ESD) protection structures supported by advanced 2-D mixed mode electro-thermal device and circuit simulation with calibrated electro-physical models to increase the reliability of protected IC’s is presented. The critical temperature as a criterion of device destruction is defined and experimentally verified. Numerical simulation and visualization of the internal electro-physical properties of the analyzed structures during a very short ESD pulse considerably improved the understanding of their physical behavior and contributes to a proper design and optimization of doping and geometry of the analyzed ESD protection devices. The analyzed devices are designed as protection against Human Body Model (HBM) and International Electromechanical Commission model (IEC) 61000-4-2 with very high robustness. The obtained results are shown on two examples. Modification of the device layout by splitting the cathode contact of the ESD diode into two parts allowing area reduction with improved electrical characteristics is the subject of the first example. The influence of doping fluctuations on the device robustness is presented in the second example. Different triggering and failure mechanisms of the diode and transistor structure during HBM and IEC pulse are presented.

TCAD simulation methodology for 3-D advanced electro-physical and optical analysis

This is first demonstrated using a full 3-D approach, where a global model includes a part of a solar cell with a textured surface. Due to device complexity, many of them cannot be simulated in the full 3-D setup within a reasonable amount of time. Therefore, derived solutions are proposed, which are based on the combined-mode setup coupling the 3-D TCAD model of the solar cell to a “standard” TCAD (2-D or 3-D) model of the active device. We propose a smart coupling between the device and the package that combines the speed and accuracy of mixed-mode simulation assuming additional 3-D effects.

TCAD simulation methodology for 3-D electro-physical and optical analysis

Numerical modeling and simulation provide an efficient tool for analysis and optimization of device structure design. In this paper we present a method for the design of solar cell. Three methodologies for fully coupled rigorous electro-physical and optical simulation of solar cell are proposed. The first one is based on full 3-D modeling employing TCAD tools applied to a simple solar cell. The second approach, using combined 2-DB-D modeling, is applied to a simple solar cell that reduces the computation time while maintaining a reasonable accuracy. In the third approach we propose a smart coupling between the device and the package that combines the speed and accuracy of mixed mode simulation assuming additional 3-D effects.

Advanced methodology for fast 3-D TCAD electrothermal simulation of power devices

In this paper the new methodology for fast 3-D electrothermal simulation of complex power devices including the package and cooling assemblies is proposed and illustrated. A power MOSFET under an unclamped inductive switching (UIS) test of the device robustness is used to perform validation of the designed electrothermal simulation. The presented simulation approach contributes to full analysis of complex structures at high speed of simulation and simplicity of implementation. The methodology is developed for co-simulation platform SMAC.

Influence of structure geometry and bulk traps on switching transients of InAlN/GaN HEMT

Impact of structure geometry and bulk traps on the performance of the n++GaN/InAlN/AlN/GaN high electron mobility transistor (HEMT) using two-dimensional Sentaurus TCAD simulation tool were investigated. Simulations were performed by the electrophysical models calibrated on real devices. The results indicate a significant influence of both acceptor and donor traps on device switching characteristics.