The influence of tilted source-drain implants on high-field effectsin submicrometer MOSFETs

Asymmetries in MOSFET high-field effects, such as impact ionization and bipolar snapback, are used to examine the influence of tilted source-drain implants on device reliability. Several process variables, including source-drain implant conditions and anneal time, are varied to determine how they affect these asymmetries. Using two-dimensional process and devices simulations to explain the physical origins of these effects, the lightly doped drain (LDD) structure is shown to offer some immunity to tilt-angle-induced reliability problems. These results are used to suggest guidelines for the design of the LDD structure