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Characterization of SiC and GaN Power Devices

Faculty: Simone Buso, Giorgio Spiazzi

Introduction

Traditionally, power electronics has been developing together with silicon based switching devices technology, from bipolar junction transistors (BJTs) and thyristors to field effect transistor (FETs) and insulated gate bipolar transistors (IGBTs). Nowadays, new materials are being considered and intensively tested, namely large energy gap semiconductors, such as SiC, GaAs and GaN. Indeed, a high energy gap device guarantees superior performance with respect to silicon from several standpoints, among which maximum voltage rating, temperature range, radiation tolerance. In addition, with these materials, high electron mobility (HEM) devices become feasible, that offer, besides the above mentioned characteristics, extremely high switching speeds, potentially approaching the GHz frontier. For these reasons, extensive research is performed worldwide, aimed at developing the future power switch technology and overcoming the current technological limitations (cost, reliability, performance degradation).

Research goals

Our group, in close cooperation with the micro-electronics and reliability research group, participates in this research, basically by developing suitable test benches for novel devices. Indeed, in the early stages of device industrialization, an intensive characterization and stress test activity is necessary to understand performance limitations and degradation mechanisms. When a potential application is identified, the power electroncs research group takes care of developing the test circuits, to define the test procedures and to analyze the achivable performance limits.

Research areas

The areas covered by the research are:

  • design of test benches for innovative switching devices (high voltage, high current, high speed, temperature controlled);
  • performance characterization of switching devices (based on Si, SiC and GaN);
  • accelerated stress tests of power switching devices.

Publications

  • G. Spiazzi, S. Buso, M. Citron, M. Corradin, R. Pierobon, "Performance Evaluation of a Schottky SiC Power Diode in a Boost PFC Application," IEEE Transactions on Power Electronics, vol.18, n.6, November, 2003, pp.1249-1253.