Junction engineering and modeling for advanced CMOS technologies

Abstract

This paper discusses an integrated modeling approach for diffusion profiles in advanced CMOS technologies. First, for USJ (Ultra-Shallow Junction) arsenic modeling, in addition to a fully-coupled model with implant damage, amorphous layer formation which depends on the Frenkel pair concentration and evolution of (311) defects and dislocation loops based on EOR (End of Range) defects are also used. Secondly, in order to improve polysilicon activation, a hybrid (arsenic + phosphorus) Source/Drain is used for NMOS. We also address the calibration of the hybrid Source/Drain for with various anneal temperatures. It is shown that modeling of the hybrid Source/Drain profile can be achieved by optimization of the dopant's Fermi level dependent diffusivity and the initial value of the point defect concentration in the equilibrium state. Finally, uphill diffusion at low anneal temperature is observed for BF2 USJ and is enhanced with Ge pre-implants. It is caused by a steep interstitial gradient created by preamorphisation and EOR damage, ultra-shallow boron profile, and boron long-hop diffusion. A BIC (Boron-Interstitial Cluster) model is employed to model boron diffusion after a spike RTA at both extension and S/D regions.