Improved Performance of 4H-SiC PiN Diodes Using a Novel Combined High Temperature Oxidation and Annealing Process

• Published in: IEEE transactions on semiconductor manufacturing 2014-08, Vol.27 (3), p.443-451
• Main Authors: Fisher, Craig A., Jennings, Michael R., Sharma, Yogesh K., Hamilton, Dean P., Gammon, Peter M., Perez-Tomas, Amador, Thomas, Stephen M., Burrows, Susan E., Mawby, Philip A.
• Format: Article
• Language: English
• Subjects: Annealing; Anodes; Carrier lifetime; Charge carrier lifetime; Diodes; Electric potential; Materials; Oxidation; PIN diodes; PIN photodiodes; Semiconductors; Temperature measurement; Transaction processing
• ISSN: 0894-6507; 1558-2345
• DOI: 10.1109/TSM.2014.2336701

In this paper, the application of a novel combined high temperature thermal oxidation and annealing process to mesa-isolated epitaxial-anode 4H-SiC PiN diodes with thick (110 μm) drift regions is presented, the aim of which was to increase the carrier lifetime in the 4H-SiC. Diodes were fabricated using 4H-SiC material having undergone this process, which consisted of a thermal oxidation in dry pure O 2 at 1550°C followed by an argon anneal at the same temperature. Forward current-voltage characterization showed that the oxidised/annealed samples typically showed around 15% lower forward voltage drop and around 40% lower differential on-resistance (at 100 A/cm 2 and 25°C) compared to control sample PiN diodes, whilst reverse recovery tests indicated a carrier lifetime increase also of around 40%. These findings illustrate that the use of this process is a highly effective and efficient way of improving the electrical characteristics of high voltage 4H-SiC bipolar devices.