Investigation on Contacts Thermal Stability for 3D Sequential Integration

Contacts stability versus thermal budget is a major concern in 3D sequential integration. We experimentally investigate the thermal stability of n-type contacts on Si and p-type contacts on SiGe in terms of specific contact resistivity (rho(c)). An improved rho(cn) performance featuring lower magnitude and better thermal stability has been demonstrated for Ti silicide contacts on n(+)-Si with Ge pre-amorphization implantation (PAI). For p-type contacts, it is found that Ni has lost its high work function advantage on p(++)-SiGe and Ti germanosilicide contacts show rho(cp) outperformance. CMOS contact scheme based on single Ti instead of dual Ti and Ni has hence been evidenced to be more suitable for 3D sequential integration.

Automated summary

The thermal stability of n-type and p-type contacts on Si and SiGe has been experimentally investigated, revealing that Ti silicide contacts with Ge pre-amorphization implantation (PAI) demonstrate better performance for n-type contacts, while Ti germanosilicide contacts show superior performance for p-type contacts. Therefore, a single Ti contact scheme has been proven to be more suitable for 3D sequential integration.