Optimum barrier layer for Al-PMD (preferential metal deposition) process

The barrier properties and the reliability of Al to Si contacts using different types of TiN in the Al-PMD process are investigated. The Al-PMD process is shown to be an excellent metallization technique for high density devices such as Giga-bit DRAMs and beyond when ACVD-TiN is used as a barrier layer. ACVD-TiN has the best diffusion barrier properties due to its high density and good conformality.