场效应管时间相关介质击穿的失效机制研究

The Time Dependent Dielectric Breakdown Failure Study of MOSFET

TDDB(Time dependent Dielectric Breakdown)时间相关介质击穿,表征与时间相关的介质电击穿。在金属场效应管器件里是用来测试栅氧层可靠性的关键参数。PEM(process evaluation module)可靠性测试片上发现,多晶叉齿结构更易造成TDDB失效。交叉实验研究表明氮化硅上顶层金属在热过程下的形变是TDDB在PEM结构上失效的主要原因。可以通过降低退火温度和氮化硅压应力的补偿来改善,可有效解决TDDB失效。同时发现介质层ILD的膜质组成也会对TDDB失效有一定影响。

TDDB （ Time dependent dielectric breakdown ） presents the dielectric＇s breakdown with time. It used for gate oxide quality check on Metal gate Oxide field devices. In PEM （process evaluation module） module reliability test, it found that TDDB is more easier failure on finger structure of CMOS Capacitance. It found the top metal＇s deformation during thermo cycling caused the FEM＇s TDDB failure. It can decrease the change by alloy temperature reducing and SiN stress compensation. Also it is helpful for TDDB failure. Meantime, the film structure of ILD is also impacted the TDDB failure base on the experiment result.