Ultra shallow junction monitoring

One of the main challenges to the scaling of CMOS devices involves the formation of ultra shallow junctions (USJ) in the source drain extension region of a transistor. This paper describes the response of a Therma-Probe™ metrology tool for the non-destructive measurement of USJ samples. Samples consisted of Boron and BF2 USJ samples fabricated with low energy implants and rapid thermal spike anneals. These junctions were measured by SIMS analysis, and their junction depths were correlated to the therma-wave signal. The thermawave response was found to be linear. The results demonstrate the ability of the Therma-Probe technique to accurately measure shallow junctions as low as 11.5nm. These types of shallow junctions are targeted around 2007, as outlined in the 2001 ITRS roadmap.