High-Interface-Quality Hf-Based Gate Stacks on Si0.5Ge0.5Through Aluminum Capping

Meng Chien Lee, Wei Li Lee, Hung Ru Lin, Guang Li Luo, Chao Hsin Chien*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


We fabricated HfO2-based gate stacks on epi-Si0.5Ge0.5 substrates and investigated the effect of Al capping on TiN. The results revealed that the Al layer formed Al2O3, which functioned as a barrier against external oxygen diffusion, resulting in excellent interface quality. Furthermore, the density of oxide traps and flat-band voltage could be tuned using various ratios of Al to TiN at the top gate. Thus, an excellent interface state density and equivalent oxide thickness (EOT) of approximately 8 $\times \,\,10^{{10}}$ eV-1cm-2 and 1.3 nm were achieved for the gate stack on SiGe through Al capping on TiN.

Original languageEnglish
Pages (from-to)1723-1726
Number of pages4
JournalIeee Electron Device Letters
Issue number12
StatePublished - 1 Dec 2021


  • Al capping
  • SiGe channel
  • interface passivation


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