Analysis of 3-Dimensional 4H-SiC MOS Capacitors Grown by Atomic Layer Deposition of Al2O3

• Published in: Materials science forum Vol. 924; pp. 490 - 493
• Main Authors: Idris, Muhammad I., Wright, Nick G., Horsfall, Alton B.
• Format: Journal Article
• Language: English
• Published: Pfaffikon Trans Tech Publications Ltd 05.06.2018
• Subjects: Aluminum oxide; Atomic layer epitaxy; Capacitance-voltage characteristics; Dimensional analysis; ALD; Sidewall; Interface State Density; 4H-SiC; Al2O3; 3-Dimentional
• ISSN: 0255-5476; 1662-9752; 1662-9752
• DOI: 10.4028/www.scientific.net/MSF.924.490

3-Dimensional 4H-SiC metal-oxide-semiconductor capacitors have been fabricated to determine the effect of the sidewall on the characteristics of 3-Dimentional gate structures. Al2O3 deposited by Atomic Layer Deposition (ALD) was used as the gate dielectric layer on the trench structure. The 3-D MOS capacitors exhibit increasing accumulation capacitance with excellent linearity as the sidewall area increases, indicating that ALD results in a highly conformal dielectric film. The capacitance – voltage characteristics also show evidence of a second flatband voltage, located at a higher bias than that seen for purely planar devices on the same sample. We also observe that the oxide capacitance of planar and 3-D MOS capacitors increases with temperature. Finally, we have found that the 3-D MOS capacitor has a weaker temperature dependence of flatband voltage in comparison to the conventional planar MOS capacitor due to the incorporation of the (1120) plane in the sidewall.