Electromigration is the transport of atoms in metal conductors at high electronic current-densities which creates voids in the conductors and increases the conductors＇ electrical resistance. It was delineated in 1961...Electromigration is the transport of atoms in metal conductors at high electronic current-densities which creates voids in the conductors and increases the conductors＇ electrical resistance. It was delineated in 1961 by Huntington; then modeled by the empirical electrical resistance formula derived by Black in 1969 to fit the dependences of the experimental electrical resistance and failure data on the electrical current density and temperature. Tan in 2007 reviewed 40-years＇ ap- plications of the empirical Black formula to conductor lines interconnecting transistors and other devices in silicon integrated circuits. Since the first Landauer theory in 1957,theorists have attempted for 50 years to justify the drift force or electron momentum transfer assumed by Black as some electron-wind force to impart on the metal atoms and ions to move them. Landauer concluded in 1989 that the electron wind force is untenable even considering the most fundamental and complete many-body quantum transport theory. A driftless or electron-windless atomic void model for metal conductor lines is reviewed in this article. It was developed in the mid-1980 and described in 1996 by Sah in a homework solution. This model accounts for all the current and temperature dependences of experimental resistance data fitted to the empiri- cal Black formula. Exact analytical solutions were obtained for the metal conductor line resistance or current, R （t）/R （0） = J（t）/J（0） = [1-2（t/τα）^1/α]^-1/2 ,in the bond-breaking limit with α = 1 to 2 and diffusion limit with α = 2 to 4,from low to high current densities, where τα is the characteristic time constant of the mechanism, containing bond breaking and diffusion rates and activation energies of the metal.展开更多
文摘为提高车辆控制算法对不同道路的适应能力,在原有学习预测控制算法的基础上,本文提出一种基于经验迁移的赛车学习预测控制策略.基于所建立的赛车曲线坐标系模型,记录小车在历史赛道上的行驶轨迹,将其作为采样安全集.采样安全集蕴含了车辆行驶的经验信息.在新赛道上,通过与采样安全集内曲率相近的轨迹进行特征匹配,找出新赛道的虚拟路径跟踪轨迹.然后,对虚拟路径跟踪轨迹附近的采样点进行坐标变换,将历史轨迹转换为新赛道的虚拟采样轨迹,实现对历史赛道上的行驶经验的迁移.构造了迁移学习预测控制(TLMPC),使小车在新的赛道上能够通过学习预测控制器以更快的速度行驶.本文在4个典型赛道上进行了仿真,结果表明所设计的控制策略控制效果有明显提升.与LMPC相比,10次迭代结果中单圈耗时至少减少了1.2 s.
文摘Electromigration is the transport of atoms in metal conductors at high electronic current-densities which creates voids in the conductors and increases the conductors＇ electrical resistance. It was delineated in 1961 by Huntington; then modeled by the empirical electrical resistance formula derived by Black in 1969 to fit the dependences of the experimental electrical resistance and failure data on the electrical current density and temperature. Tan in 2007 reviewed 40-years＇ ap- plications of the empirical Black formula to conductor lines interconnecting transistors and other devices in silicon integrated circuits. Since the first Landauer theory in 1957,theorists have attempted for 50 years to justify the drift force or electron momentum transfer assumed by Black as some electron-wind force to impart on the metal atoms and ions to move them. Landauer concluded in 1989 that the electron wind force is untenable even considering the most fundamental and complete many-body quantum transport theory. A driftless or electron-windless atomic void model for metal conductor lines is reviewed in this article. It was developed in the mid-1980 and described in 1996 by Sah in a homework solution. This model accounts for all the current and temperature dependences of experimental resistance data fitted to the empiri- cal Black formula. Exact analytical solutions were obtained for the metal conductor line resistance or current, R （t）/R （0） = J（t）/J（0） = [1-2（t/τα）^1/α]^-1/2 ,in the bond-breaking limit with α = 1 to 2 and diffusion limit with α = 2 to 4,from low to high current densities, where τα is the characteristic time constant of the mechanism, containing bond breaking and diffusion rates and activation energies of the metal.
