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-电压关系的集总参数描述来建模行为。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，以带宽和/或时钟速度为特征的当前系统工作频率以与积分密度的摩尔定律类似（甚至更快）的速率增加。随着电路中工作频率（或时钟速度）的增加，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。 在太赫兹和远红外区的更高频率下，人们必须考虑辐射吸收和发射，包括与整个环境的相互作用。这种更高的频率范围不仅从越来越高的速度设备和电路中接近，而且从光电子学方面，因为长波长源和检测器正在寻求新的光通信信道，以及各种特殊用途的应用，如传感。这就需要开发新的CAD工具，结合电磁理论和半导体器件的概念。这种方法被称为全局建模，指的是它能够使用一个统一的schema.here模型完整的电路提出了一个为期三年的研究计划的资金，其目标是开发设备和电路仿真工具，准确模拟高频电子电路，以及长波长的光电子系统。这些半导体器件工具将采用在先前NSF资助下开发的基于全频带元胞自动机/蒙特卡罗粒子的技术，用于半经典玻尔兹曼输运方程的高效精确物理解，与较低级别的模型（如流体动力学求解器和分布式晶体管行为模型）分层耦合。这些技术将结合强大的现场求解器的基础上全波解决方案的麦克斯韦方程组使用有限差分时域（FDTD）技术。耦合FDTD/Device问题的3D解决方案从计算的角度来看是具有挑战性的，因此很大一部分的努力将解决算法的改进，包括并行化在分布式workstation environment. Device/FDTD仿真内核将被嵌入到一个更大的模拟域，例如无源元件和带状线耦合的匹配电路放大器。 模拟工具的比较和校准将与工业伙伴合作进行。从工业合作者获得的设备上的高频散射参数测量将用于使用上述技术校准全局模拟结果。PI将重点关注高频放大器技术（例如GaAs MESFET和HFET技术）以及更先进的材料系统（例如SiGe HBT和GaN场效应晶体管）的建模。 对于功率放大器应用，也将考虑热效应。他们还将把拟议的模拟工具应用于太赫兹源和探测器的研究，例如用于电光采样，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