Ultrathin Interfacial Layer (UTIL) Formation and Its Application in HKMG for Advance CMOS Technology

Abstract

This paper investigates two kinds of ultra thin interfacial layer (UTIL) include SiO2 and SiON, their formation and application in HKMG for advanced CMOS technology. Compare to SiO2 UTIL, SiON UTIL demonstrates good NMOS EOT uniformity, low gate leakage current, but high defect density. Beside offline characterization, these two kinds of interfacial layer were also investigated their application in semiconductor device wafer for electronic test. It is found that the ultrathin SiON as interfacial layer exhibits a lower Tinv and better leakage performance under same physical thickness as compared to SiO2. However, PMOS device mobility suffers some degradation, which is contributed to N diffusion into the interface between UTIL and substrate, as verified by N SIMS profile. Different N atom concentration and thickness of UTIL SiON and their impact on device performance were also discussed in this paper. In general, UTIL SiON film is a promising candidate interfacial layer for HKMG advanced CMOS technology to meet EOT scaling requirement.