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Unformatted text preview: Interfacial characteristics of N 2 O and NO nitrided SiO 2 grown on SiC by rapid thermal processing Hui-feng Li, Sima Dimitrijev, H. Barry Harrison, and Denis Sweatman School of Microelectronics Engineering, Griffith University, Nathan, QLD 4111, Australia ~ Received 20 September 1996; accepted for publication 10 February 1997 ! Interfacial characteristics of Al/SiO 2 / n-type 6H–SiC metal–oxide–semiconductor capacitors fabricated by rapid thermal processing ~ RTP ! with N 2 O and NO annealing are investigated. Interface state density was measured by a conductance technique at room temperature. RTP oxidation in pure O 2 leads to an excellent SiO 2 / n-type 6H–SiC interface with interface state density in the order of 10 10 – 10 11 eV 2 1 cm 2 2 . NO annealing improves the SiO 2 / n-type 6H–SiC interface, while N 2 O annealing increases the interface state density. © 1997 American Institute of Physics. @ S0003-6951 ~ 97 ! 04415-X # In recent years SiC has attracted considerable interest because of its wide band-gap ~ 2.9 eV for 6H–SiC ! proper- ties, which promises high-temperature, high-frequency, and high-power electronic devices. 1 The growth of high-quality SiO 2 on SiC is a crucial step to realize these applications. The fact that SiC can be oxidized in a conventional way similar to Si is a great advantage over other wide band-gap semiconductors. Although considerable work has been re- ported on the growth of SiO 2 on SiC using dry and wet oxidation processes with postannealing in nitrogen or argon, 2–6 little work has been reported so far on the nitrida- tion of oxides grown on SiC. As nitridation of oxides grown on Si wafers leads to an improved SiO 2 /Si interface, 7–9 it is very important to study the effects of nitridation on oxides grown on SiC. We recently reported the capacitance–voltage ( C – V ) measurement of N 2 O and NO nitridation of SiO 2 grown on 6H–SiC. 10 For n-type 6H–SiC, NO annealing led to the improvement of metal–oxide–semiconductor ~ MOS ! capacitor C – V curves, while N 2 O annealing caused C – V curve stretching compared to that of the as-grown oxide. Here, we report on interface measurements for SiO 2 grown on n-type 6H–SiC in pure O 2 and, subsequently, annealed in N 2 O and NO ambient. Silicon faced 6H–SiC wafers used in our work were nitrogen doped with a concentration of 4.8 3 10 17 cm 2 3 manufactured by CREE Research. The 6H–SiC wafers were cleaned by a mixture of H 2 SO 4 and H 2 O 2 and then by a standard RCA cleaning followed by a 1% HF dip prior to the oxidation. The SiO 2 was grown in an AG610™ rapid thermal processing ~ RTP ! unit. Six 5 min steps in high-purity O 2 at around 1100 °C ~ 30 min of total oxidation ! were used to grow the oxide. The thickness was estimated from high- frequency C – V curves to be 3.5 nm. After the oxidation, two sets of samples were further exposed to NO or N 2 O annealing, respectively, for an additional 5 min at around 1100 °C. Aluminum was evaporated and 3001100 °C....
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This note was uploaded on 12/10/2009 for the course IF PFIS1200 taught by Professor Antonio during the Spring '09 term at Universidade Federal do Rio de Janeiro.
- Spring '09