多值共振遂穿电路设计方法研究

With the characteristic dimension of devices has been decreased to nanometer scale, and more and more requirements to the high performance of devices, the Moore's Law and scaling rule could not satisfy the development of VLSI. Resonant tunneling devices based on the quantum effect are more suitable than the traditional transistors in the future development of IC, its characteristics of ultra-high-speed, ultra-high-frequency, ultra-high-integration density, high efficiency, low power loss, design flexibility and the physical structure determine its feasibility and robustness in the multiple-valued logic design. The applications of multiple-valued logic can effectively reduce chip area and the pins as well as wiring between the systems, and have the remarkable merits in the signal transmission and storage. Resonant tunneling devices and multiple-valued logic will be one of the development trends of integrated circuit in the future. .Therefore in this project we will focus on the research of design methods for the multiple-valued resonant tunneling circuits from the circuit and system level, propose the multiple-valued resonant tunneling diode switch circuit model, establish the switch threshold table, create the multiple-valued switch-transmission algebra system, define correlation operations and mathematical signs, design correlation sub-operation structures, optimize the multiple-valued truth table and extend the three-dimension multiple-valued Karnaugh Map, discuss the applications of multiple-valued switch circuit model and algebra system in resonant tunneling multiple-valued basic logic units and multiple-valued memory circuits design. This topic will have great significance to the multiple-valued resonant tunneling circuits design, can be used to guide the higher-valued and more complex circuit designs, offer a novel, simple design idea and method, and lay the theoretical foundation for the development of the multiple-valued digital integrated circuits based on resonant tunneling devices.

随着器件特征尺寸不断减小，对器件性能的要求越来越高，摩尔定律和按比例缩小的方法已经不再满足集成电路发展要求。基于量子效应的共振隧穿器件比传统的晶体管等更适合未来集成电路的发展，超高速、超高频、超高集成度、高效低功耗、设计灵活等特点和物理结构决定了其在多值逻辑设计中的可行性及稳健性。而应用多值逻辑能有效减小集成电路芯片面积与引脚以及系统间的接线，在信号传输和存储方面有着显著的优点。共振隧穿器件以及多值逻辑将是未来集成电路发展的趋势之一。.因此本项目将从电路与系统层面出发，研究多值共振隧穿电路的设计方法，提出基于共振隧穿二极管的多值开关电路模型，建立开关状态阈值表，构建多值翻转-传输代数系统，定义联结运算及数学符号，设计联结子运算电路结构，优化多值真值表及扩展三维多值卡诺图，探讨多值开关电路模型及代数系统在共振隧穿多值基本逻辑单元和多值存储电路设计中的应用。本课题对多值共振隧穿电路的设计具有重要意义，提供了全新的、简单的设计思路和设计方法，可用于指导更高值和更复杂电路结构的设计，为基于共振隧穿器件的多值数字集成电路发展奠定了理论基础。

本课题在国家自然科学基金项目的资助下，重点开展了基于多值共振遂穿器件RTD（Resonant Tunneling Diode）的电学特性分析、器件建模、参数波动对器件特性影响的统计方法研究、多值共振遂穿电路设计方法研究。.建立了共振遂穿对称双势垒RTD数值分析模型，得到了适合低压低功耗对称双势垒RTD结构多值逻辑MVL（Multiple-valued logic）应用的参数；研究了势垒材料对非对称势垒GaAs基RTD器件电学特性的影响，分析了势阱和势垒宽度对GaAs/AlGaAs基对称DBS RTD负阻特性影响的规律。课题对GaN系多负阻区多值RTD器件特性也进行了研究，通过改进GaN系RTD器件的结构参数，对多负阻区多值RTD特性曲线进行了优化，使其能更好地应用于MVL电路。为多值共振遂穿电路的设计奠定了初步的器件物理和数学理论基础。.通过对器件电学特性以及器件参数波动对电学特性影响的研究，分析了由于随机掺杂波动造成的纳米器件特性参数的变化，建立了晶体管截止频率、栅极长度、栅极总电容与跨导、掺杂浓度之间的参数变化关系。将晶体管这些规律特性和行为应用于RTD的MOS-NDR负阻特性仿真模型，为共振遂穿器件纳米尺度模型的建立提供了理论基础和试验参考数据，并为基于共振遂穿器件多值逻辑电路的初步自动化设计与仿真验证提供了支撑。.提出了基于共振遂穿器件的多值文字运算电路的设计方法。通过对器件状态的分析、多值逻辑布尔代数系统的推导、数学逻辑表达式的化简、电路结构实现的流程化方案，把卡诺图与多值遂穿电路布尔代数系统相结合，设计了以文字电路为核心的多值T触发器，具有预置功能的改进型多值JK同步型触发器等电路结构，并通过仿真验证了正确性；研究了共振遂穿电路中几种存储电路与文字运算之间的逻辑关系，以及各种多值共振遂穿触发器例如D触发器、JK触发器和T触发器之间的逻辑关系和相互转化。