Nitric acid oxidation method to form SiO2/3C–SiC structure at 120 °C

✍ Scribed by Sung-Soon Im; Sumio Terakawa; Hitoo Iwasa; Hikaru Kobayashi

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 438 KB
• Volume: 254
• Category: Article
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2007.10.102

✦ Synopsis

3C-SiC(0 0 1) surfaces are considerably rough with the roughness root mean square value (R ms ) of 1.3 nm, but the surfaces become considerably smooth (i.e., R ms of 0.5 nm) by heat treatment in pure hydrogen at 400 8C. Two-step nitric acid (HNO 3 ) oxidation (i.e., immersion in $40 wt% HNO 3 followed by that in 68 wt% HNO 3 ) performed after the hydrogen treatment can oxidize 3C-SiC at extremely low temperature of $120 8C, forming thick SiO 2 (e.g., 21 nm) layers. With no hydrogen treatment, the leakage current density of the hAl/SiO 2 /3C-SiCi metal-oxidesemiconductor (MOS) diodes is high, while that for the MOS diodes with the hydrogen treatment is considerably low (e.g., $10 À6 A/cm 2 at the forward gate bias of 1 V) due to the formation of uniform thickness SiO 2 layers. The MOS diodes with the hydrogen treatment show capacitancevoltage curves with accumulation, depletion, and deep-depletion characteristics.