Simulation of High Speed Pseudomorphic Heterojunction Bipolar Transistors

一个具体目标是扩大 数值模拟的最新进展 晶格匹配异质结 半导体器件到应变层 （赝晶）异质结 高速半导体器件 和/或高频应用。 超过 在过去的三年里，我们 A1GaAs/GaAs和InGaAs/InA1AsHBT。 使用 有限差分漂移扩散 方程（DDE）求解器和数值 小信号交流终端分析 特性以及fT和fmax 这些装置已经被模拟。 在 应变层研究近况 半导体，这是自然的延伸， 我们目前的研究， 涉及应变层的HBT。 重点 将被放置在Si 1-x格克斯/Si和InxGa 1-x上 As/GaAs系统。 基本异质结 要建模的结构是垂直的 具有应变双极晶体管的器件 具有发射极顶部或 收集器顶部配置。 的Monte 将使用Carlo方法来确定 基本材料特性，例如 迁移率，不同的耦合常数 需要适当的建模， 稳态效应，如过冲，以及 进行全面的区域分析， 这些影响的选定区域 怀疑正在发生的，例如， HBT的基极-集电极区。 在 下一步，将进行计算 使用从以下方程获得的流体动力学方程： 玻尔兹曼方程的前三阶矩 输运方程 从MC数据导出的系数。 这些计算的结果将 使我们能够计算稳态 直流和小信号交流参数， 范围从电流增益到fT和fmax。 模拟结果将与 无论是公布的数据还是实际的 设备测量将在 与IBM研究人员的合作 Corporation. 希望这一 研究将使异质结 今天发达国家的优势 硅技术，也采取砷化镓 技术在竞争中更进一步 最快的半导体器件。

A specific objective is to extend the state-of-the-art of the numerical modeling of lattice-matched heterojunction semiconductor devices to strained-layer (pseudomorphic) heterojunction semiconductor devices for high speed and/or high frequency applications. Over the last three years, we have modeled A1GaAs/GaAs and InGaAs/InA1AsHBTs. Using a finite difference drift-diffusion equations (DDE) solver and numerical small-signal a.c. analysis, terminal characteristics as well as fT and fmax of these devices have been simulated. In view of recent interest in strained-layer semiconductors, it is natural to extend our current research to the modeling of HBTs involving strained layers. Focus will be placed on Si1-x Gex/Si and InxGa1-x As/GaAs systems. The basic heterojunction structures to be modeled are vertical devices having strained double heterojunctions with either emitter-top or collector-top configurations. The Monte Carlo method will be used to determine fundamental material properties, e.g. mobility, different coupling constants needed for proper modeling of non- stationary effects such as overshoot, and to perform full regional analysis of selected regions where these effects are suspected to be taking place, e.g. in the base-collector region of an HBT. In the next step, calculations will be performed using hydrodynamic equations obtained from the first three moments of the Boltzmann transport equation with the transport coefficients derived form the MC data. The results of these calculations will enable us to calculate both steady state d.c. and small-signal a.c. parameters, ranging from current gain to fT and fmax. Simulation results will be compared with either published data or with actual device measurements to be carried out in collaboration with researchers of the IBM Corporation. It is hoped that this research will bring heterojunctions advantages to today's well developed silicon technology and also take GaAs technology one step further in the race for the fastest semiconductor device.