Ramped current stress for fast and reliable wafer level reliability monitoring of thin gate oxide reliability

Reliability of gate dielectrics and metal–insulator–metal capacitors

“…4 displays the V bd distribution of a PMOS 2.2 nm gate oxide measured with an ERCS. It illustrates that when only the hard breakdown event is plotted, the cumulative failure distribution does not represent the correct oxide characteristic and indicates a lower Weibull slope [18].…”

“…Still the most challenging task is the reliable automatic detection of a breakdown event whether soft or hard breakdown had occurred [18] and whether it is a thick or ultra-thin SiO 2 layer [48]. The definition of an appropriate breakdown criteria is dependent on the test structure layout, the reliability stress method, the breakdown type, the tester hardware and the dielectric layer characteristics.…”

“…In order to be able to monitor such a soft breakdown the standard constant [17,19,21,48] or ramped stress measurement [16,18,20,45] must be modified. Fig.…”

“…A competitive method for soft breakdown detection is the determination of a noise figure from the measured data. This has been proven to work for CVS [19] and even for fast ERCS [18,20] and offers the advantage of no extra time being used for additional measurements.…”

“…at breakdown Vbd [V] earliest breakdown event detected hard breakdown Cumulative failure probability ln(-ln(1-F)) Weibull distribution of intrinsic V bd of a PMOS 2.2 nm gate oxide measured with an ERCS showing only hard breakdown or the first breakdown event[18].…”