The Improved Reliability Performance of Post-Deposition Annealed ALD-SiO₂

Abstract:

A systematic capacitance-voltage (C-V) and time-dependent dielectric breakdown (TDDB) study on silicon carbide (SiC) metal-oxide-semiconductor capacitors (MOSCAPs) that use silicon dioxide (SiO₂) is shown in this paper. Oxides were formed using atomic layer deposition (ALD), low-pressure chemical vapour deposition (LPCVD) or direct thermal growth in nitrous oxide (N₂O) ambient, where both deposited oxides were post-deposition annealed in N₂O ambient, too. The electrical characterisation results reveal that the ALD-deposited and N₂O-annealed oxides show the best capacitance-voltage (C-V) characteristics, with flatband and hysteresis voltages (V_FB) averaging 1.44 V and 0.41 V, respectively. When measuring the leakage current levels at 175°C, the ALD-deposited MOSCAPs’ breakdown electric fields are averaging similar to their counterparts at 9.71 MV/cm. MOSCAPs which utilized ALD-deposited SiO₂ also showed 29% and 345% increased average injected charge-to 63% failure (Q_BD,63%) at 9 MV/cm and 9.6 MV/cm, respectively, when comparing these devices to their direct thermally grown SiO2 counterparts.

• Periodical: Materials Science Forum (Volume 1062)
• Pages: 325-329
• DOI: https://doi.org/10.4028/p-b76y6c
• Online since: May 2022
• Authors: A. Benjamin Renz*, Oliver James Vavasour, Peter Michael Gammon, Fan Li, Tian Xiang Dai, G.W.C. Baker, Nicholas Grant, John D. Murphy, Philip Andrew Mawby, Vishal Ajit Shah
• Keywords: 4H-SiC, Atomic Layer Deposition, MOSCAP, N₂O, Post-Deposition Annealing, Reliability, SiO₂, TDDB

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