Effects of wet-oxidized 4H-SiC annealed in HNO3/H2O vapour
Abstract
Purpose
The high density of defects mainly attributed to the presence of silicon oxycarbides, residual C clusters, Si- and C-dangling bonds at or near the SiO2/SiC interface degrades the performance of metal-oxide-semiconductor (MOS) devices. In the effort of further improving the quality and enhancement of the SiC oxides thickness, post-oxidation annealed by a combination of nitric acid (HNO3) and water (H2O) vapor technique on thermally grown wet-oxides is introduced in this work. The paper aims to discuss these issues.
Design/methodology/approach
A new technique of post-oxidation annealing (POA) on wet-oxidized n-type 4H-SiC in a combination of HNO3 and H2O vapor at various heating temperatures (70°C, 90°C and 110°C) of HNO3 solution has been introduced in this work.
Findings
It has been revealed that the samples annealed in HNO3 + H2O vapour ambient by various heating temperatures of HNO3 solution; particularly at 110°C is able to produce oxide with lower interface-state density and higher breakdown voltage as compared to wet-oxidized sample annealed in N2 ambient. The substrate properties upon oxide removal show surface roughness reduces as the heating temperature of HNO3 solution increases, which is mainly attributed due to the significant reduction of carbon content at the SiC/SiO2 interface by C=N passivation and CO or CO2 out-diffusion.
Originality/value
Despite being as a strong oxidizing agent, vaporized HNO3 can also be utilized as nitridation and hydrogen passivation agent in high temperature thermal oxidation ambient and these advantages were demonstrated in 4H-SiC.
Keywords
Acknowledgements
This work was partly supported by the Power Generation & Electricity Delivery of Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant which was funded by the Korea Government – Ministry of Knowledge Economy (No. 2009101030002A) and eScienceFund (6013385) of Ministry of Science, Technology, and Innovation (MOSTI), Malaysia. One of the authors (BP) would like to acknowledge the financial support given by Universiti Sains Malaysia (USM) through Postgraduate Fellowship Program (RU(1001/441/CIPS/AUPE001)).
Citation
Poobalan, B., Hyun Moon, J., Kim, S.-C., Joo, S.-J., Bahng, W., Ho Kang, I., Kim, N.-K. and Yew Cheong, K. (2014), "Effects of wet-oxidized 4H-SiC annealed in HNO3/H2O vapour", Microelectronics International, Vol. 31 No. 1, pp. 42-53. https://doi.org/10.1108/MI-08-2013-0038
Publisher
:Emerald Group Publishing Limited
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