Effect of Al doping on the reliability of ALD HfO2

M. N. Bhuyian, D. Misra, K. Tapily, R. D. Clark, S. Consiglio, C. S. Wajda, G. Nakamura, G. J. Leusink

Research output: Contribution to journalConference articlepeer-review

Abstract

This work has demonstrated a high quality HfO2 based gate stack by depositing atomic layer deposited (ALD) HfAlOx along with HfO2 in a layered structure. In order to get multifold enhancement of the gate stack quality both Al percentage and distribution were observed by varying the HfAlOx layer thickness and it was found that < 2% Al/(Al+Hf)% incorporation can result in up to 18% reduction in average EOT along with up to six fold reduction in gate leakage current as compared to the dielectric with no Al content. On the other hand, excess Al presence in the interfacial layer moderately increased the interface state density (Dit). When devices were stressed in the gate injection mode at a constant field stress dielectrics with Al/(Hf+Al)% ∼ 2% showed resistance to stress induced flatband voltage shift (δVFB), and stress induced leakage current (SILC). The time dependent dielectric breakdown (TDDB) characteristics of these devices showed a reduced charge to breakdown and an increase in the extracted Weibull slope (β]) that further confirms an enhanced dielectric reliability.

Original languageEnglish (US)
Pages (from-to)29-43
Number of pages15
JournalECS Transactions
Volume64
Issue number8
DOIs
StatePublished - Jan 1 2014
EventSymposium on Semiconductors, Dielectrics, and Metals for Nanoelectronics 12 - 2014 ECS and SMEQ Joint International Meeting - Cancun, Mexico
Duration: Oct 5 2014Oct 9 2014

All Science Journal Classification (ASJC) codes

  • Engineering(all)

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