Addressing Key Challenges for SiGe-pFin Technologies: Fin Integrity, Low-DIT Si-cap-free Gate Stack and Optimizing the Channel Strain

Abstract

This paper shows the importance of oxygen control at the SiGe fin surface and within the gate stack. Optimized SiN liners are required to protect SiGe fins from oxidation during a flowable CVD (FCVD) densification anneal. Suppression of oxygen diffusion or scavenging from GeO via metal electrode is essential to achieve a low-DIT SiGe gate stack. By replacing HfO2 with other dielectrics offering lower oxygen diffusivity, impact of metal electrode deposition process as well as the HfO2 nitridation is corroborated to be related to the oxygen diffusivity. Finally, when using an embedded B-doped Si0.4Ge0.6S/D, higher channel strain in Si0.7Ge0.3 than in Si p-fins is obtained as predicted by TCAD.