Quiet Enablers of Modern Life

Every electronic appliance needs some kind of power supply. Being mobile and connected are ultimate design goals for most personal computing devices. On the other hand, the enabling technology is often wireless communication, using rdio-frequency (RF) circuits in its physical layer. In both cases, embedded analog circuits need electron devices optimized for high power, ultimate speed, low distortion and/or harsh operating conditions (temperatures, radiation).

As some technology solutions originating from mainstream digital microelectronics are being applied in this area, they generate demand for reliable, flexible and accurate EDA tools. Key requirements are simulation of circuits in mixed-mode, device variability, device and circuit self-heating, detailed convergence control, and the ability to consider a variety of materials.

Power

Electric car charging
At the turn of the millennium, many discrete power electronic components were replaced by modified MOS devices (VMOS, (L)DMOS) processed in adapted legacy submicron foundries and integrated with logic circuits, memory and sensors – resulting in Power System on Chip (PSoC). Since silicon as a material has limitations, new wide band gap materials (SiC, GaN) were introduced to power devices design.

Because of their inherent distributed nature of electrical conduction and many physical effects and interactions, 2D/3D TCAD tools/device simulators are especially useful in design and optimization of high-power solid-state devices. Based on electric field, current density, lattice temperature, or impact ionization distribution from simulation results, device structures can be optimized.

GTS Minimos-NT is the ideal tool for this job, proven as well as versatile. All relevant semiconductor materials (e.g. Si, SiC, GaN) are supported in the material database, accompanied by calibrated physical models. Templates and examples for common devices (MESFET, DMOS, LDMOS) are available and can be parametrically modified to fit customer requirements. To simulate behavior at high electric fields, several impact ionization models are available. Simulation of the full breakthrough curve with snapback effect can be performed using sequential voltage and current stepping. Self-heating effects can be included in the solution easily. Finally, the optimizer included in GTS Framework can be used to fine-tune for the desired result.

SiC SBD forward characteristics vs. T
SiC SBD breakthrough characteristic with snapback
Impact ionization rate in SiC SBD
Electron current density in SiC SBD
SiC MESFET output characteristics
SiC MESFET potential distribution for high current
SiC MESFET lattice temperature for high current
LDMOS Output characteristics
LDMOS
LDMOS electron current density

Radio-Frequency (RF)


For wireless connectivity (regardless of the appliance, protocol or application), some kind of RF front-end is integrated using electron devices optimized for high-speed operation, e.g. High Electron Mobility Transistor (HEMT), Heterojunction Bipolar Transistor (HBT) or Metal Semiconductor FET (MESFET). More frequently than Si, compound semiconductors are used as channel material: GaAs, SiGe, GaN, InP, SiC, or even diamond (C).

Thanks to the rich material database, proven and consistent algorithms, various physical models, and available simulation modes (AC, transient analysis), GTS Framework is ideal for simulating RF electron devices and circuits. While originally developed for mainstream Si digital logic, GTS Minimos-NT shows its strenghts at quantum confinement effects and mobility models for simulation of advanced structures, e.g. HEMT transistors. They can be used with Drift-Diffusion (DD) or Hydrodynamic (HD) iteration schemes. The conditional stepping feature of the simulator is useful for determining certain threshold device parameters (e.g. cut-off frequency). DoE and Optimizer are easily configurable in GTS Framework to explore device design space or to narrow limits on a design parameter.

GaN HEMT
GaN HEMT with T-gate
GaN HEMT transfer characteristics
Electron concentration in GaN HEMT
GaN HEMTs current gain
GaN HEMTs cut-off frequency

Consistent and Versatile Simulation for Analog Domain

Solid physical foundations and a rich material database make GTS simulation tools very useful in design of contemporary semiconductor devices and analog circuits for power and RF applications. Additional physical models of the classical simulator Minimos-NT (e.g. self-heating, impact ionization) and visualizations of internal variable distributions are indispensable in optimizing device structures. Mixed mode circuit/device simulations in AC or transient mode put these devices in realistic environments and can be used to extract performance indicators. Data processing scripts and a Python API included in GTS Framework make it easy to customize your simulation flow for a particular application.

 

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GTS Minimos NT – simulate semiconductor devices and circuits: Run steady-state, transient, and small-signal analysis of arbitrary 2D and 3D device geometries. Combine multiple devices in a circuit with compact models. Run thermal analysys of devices and circuits.