LIGHTLY DOPED DRAIN EXTENSION PROCESS TO MINIMIZE SOURCE/DRAIN RESISTANCE WHILE MAINTAINING HOT CARRIER LIFETIME

摘要

The process flow in the fabrication of MOSFETs having a LDD is altered by using a combination of arsenic and phosphorus to tailor the lateral profile to meet both series resistance and channel hot carrier requirements. In this process flow, the relatively higher dose arsenic controls the series resistance and the lighter phosphorus dose sets the lateral junction profile. Therefore, a profile intermediate the arsenic only and the phosphorus only can be achieved. In forming a LDD in accordance with the present invention, the arsenic implant dose is relatively high. The lateral extend of the LDD is varied to meet the hot carrier lifetime by varying the lighter phosphorus implant dose. This procedure is achieved using standard process technology.