Reduction of interface states in Ge/High-k gate stacks and its reliability implications

Misra, D and Ding, YM and Mukhopadhyay, S and Ganapathi, KL and Bhat, N (2016) Reduction of interface states in Ge/High-k gate stacks and its reliability implications. In: 13th IEEE International Conference on Solid-State and Integrated Circuit Technology, ICSICT 2016, 25-28 October 2016, Hangzhou, pp. 499-503.

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Abstract

This work reviews a process that was developed to enhance the interface state density of a Ge/High-k interface. A slot plane antenna plasma oxidation (SPAO) process was implemented during dielectric deposition steps to fabricate TiN/ZrO2/Al2O3/p-Ge MOS gate stacks. A poor interface was observed with SPAO being performed before Al2O3/ZrO2 gate stack deposition because of fragmented GeOX interfacial layer formation. Significant decrease in interface state density was observed because of the formation of a stable and moderately thick GeOX interfacial layer when SPAO was performed in between Al2O3/ZrO2 deposition. When SPAO was performed after the deposition of both the high-k layers, higher Dit was observed suggesting a GeO2 layer formation. Time Dependent Dielectric Breakdown (TDDB) measurements suggest that stable and moderately thick GeOX interfacial layer (SPAO was in-between the two high-k layers) provides better immunity to degradation under stress. It was further observed that if GeO2 is at the interface then it degrades at a faster rate. The trap distribution in dielectric layers and interfacial layer properties contribute to the dielectric breakdown. SPAO seems to be an excellent processing step during high-k deposition to enhance the Ge/High-k devices.

Item Type:	Conference Paper
Publisher:	Institute of Electrical and Electronics Engineers Inc.
Additional Information:	The copyright for this article belongs to the Institute of Electrical and Electronics Engineers Inc.
Keywords:	Equivalent oxide thickness (EOT); Flat-band voltage shift (Δ VFB); Interface state density (Dit); SPAO; Stress induced leakage current (SILC); Time dependent dielectric breakdown (TDDB)
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	06 Jun 2022 06:50
Last Modified:	06 Jun 2022 06:50
URI:	https://eprints.iisc.ac.in/id/eprint/73249

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