Global Modeling of HIgh Frequency Circuits and Devices

分析电路和/或系统的传统方法是根据电流-电压关系的集中参数描述来对行为进行建模。因此，器件、电路和系统建模通常简化为建立描述集总电路元件的I-V特性的参数。然而，目前以带宽和/或时钟速度为特征的系统操作频率正在以与积分密度的摩尔定律类似(甚至更快)的速度增长。随着电路中工作频率(或时钟速度)的增加，人们必须将信号视为在传输线上传播的电磁波，而不是简单的电压和电流。在太赫兹和远红外的更高频率下，人们必须考虑辐射的吸收和发射，包括与整个环境的相互作用。随着长波长源和探测器被用于新的光通信信道，以及各种特殊用途的应用，例如传感，人们不仅从越来越高速的器件和电路接近这种更高频率的体制，而且从光电子学方面也在接近这种更高频率的体制。这就需要开发结合了电磁理论和半导体器件概念的新的CAD工具。这种方法被称为全局建模，指的是它使用一个统一的方案对完整电路进行建模的能力。这里建议为一个为期三年的研究计划提供资金，目标是开发器件和电路模拟工具，用于精确模拟高频电子电路和长波长光电子系统。这些半导体器件工具将采用全频带元胞自动机/蒙特卡罗粒子技术，该技术是在以前的NSF资助下开发的，用于半经典Boltzmann输运方程的高效精确物理解，并与诸如流体动力学求解器等较低级别的模型和分布式晶体管行为模型分层耦合。这些技术将与基于使用时域有限差分(FDTD)技术的麦克斯韦方程的全波解的健壮的场解算器相结合。从计算角度来看，耦合FDTD/Device问题的3D解决方案具有挑战性，因此很大一部分工作将涉及算法改进，包括分布式工作站环境中的并行化。Device/FDTD仿真内核将嵌入更大的仿真域，例如表示放大器匹配电路的无源元件和带状线耦合。将与工业伙伴合作，对模拟工具进行比较和校准。从工业合作者那里获得的设备上的高频散射参数测量将被用来使用上述技术来校准全球模拟结果。PIS将侧重于高频放大器技术的建模，如GaAs MESFET和HFET技术，以及更先进的材料系统，如SiGe HBT和GaN场效应管。对于功率放大器应用，还将包括热效应的考虑。他们还将把建议的模拟工具应用于太赫兹源和探测器的研究，例如在电光采样中使用，其中将与超快光开关测量进行比较

0115548GoodnickThe conventional approach to analyzing circuits and/or systems is to model the behavior in terms of lumped-parameter descriptions of the current-voltage relationships. Hence, device, circuit, and system modeling is often reduced to establishing the parameters that describe I-V characteristics of lumped circuit elements. However, present system operating frequencies characterized in terms of bandwidth and/or clock-speed are increasing at a rate analogous (and even faster) than Moore's law for integration density. As the operating frequency (or the clock speed) increases in circuits, one must treat the signals as electromagnetic waves propagating on transmission lines, rather than the simple voltages and currents. At even higher frequencies in the tera-hertz and far-infrared regime, one has to account for radiation absorption and emission including the interaction with the whole environment. This higher frequency regime is not only being approached from increasingly higher speed devices and circuits, but also from the optoelectronics side as long-wavelength sources and detectors are sought for new optical communication channels, as well as a variety special use applications such as sensing. This requires the development of new CAD tools that combines both electromagnetic theory and semiconductor device concepts. This approach is known as Global Modeling referring to its ability to model complete circuits using one unified scheme.Herein is proposed funding for a three-year program of research with the goal of developing device and circuit simulation tools for accurate simulation of high frequency electronic circuits as well as long-wavelength optoelectronic systems. These semiconductor device tools will employ a full-band Cellular Automata/Monte Carlo particle-based techniques developed under previous NSF funding for efficient accurate physical solution of the semi-classical Boltzmann transport equation, coupled hierarchically with lower level models such as hydrodynamic solvers, and distributed transistor behavioral models. These techniques will be combined with robust field solvers based on full-wave solutions of Maxwell's equations using finite difference time domain (FDTD) techniques. The 3D solution of the coupled FDTD/Device problem is challenging from a computational standpoint, hence a large fraction of effort will address algorithmic improvements including parallelization in a distributed workstation environment.The device/FDTD simulation kernel will be embedded in a larger simulation domain representing for example the passive elements and stripline coupling of the matching circuit for an amplifier. Comparison and calibration of the simulation tools will be performed in collaboration with industrial partners. High frequency scattering parameter measurements on devices obtained from industrial collaborators will be used to calibrate global simulation results using the above techniques. The PIs will focus on the modeling of high frequency amplifier technologies such as GaAs MESFET and HFET technology, as well as more advanced material systems such as SiGe HBTs and GaN field effect transistors. Consideration of thermal effects will be included as well for power amplifier applications. They will also apply the proposed simulation tool to the investigation of tera-hertz sources and detectors used for example in electro-optic sampling, where comparison will be made to ultrafast optical switching measurements