Fabrication and Characterization of 3C- and4H-SiC MOSFETs

During the last decades, a global effort has been started towards the implementation of energy efficient electronics. Silicon carbide (SiC), a wide band-gap semiconductor is one of the potential candidates to replace the widespread silicon (Si) which enabled and dominates today’s world of electronics. It has been demonstrated that devices based on SiC lead to a drastic reduction of energy losses in electronic systems. This will help to limit the global energy consumption and the introduction of renewable energy generation systems to a competitive price. Active research has been dedicated to SiC since the 1980’s. As a result, a mature SiC growth technology has been developed and 4 inch SiC wafers are today commercially available. Research and development activities on the fabrication of SiC devices have also been carried out and resulted in the commercialization of SiC devices. In 2011, Schottky barrier diodes, bipolar junction transistors, and junction field effect transistors can be purchased from several electronic component manufacturers. However, the device mostly used in electronics, the metal-oxide-semiconductor field effect transistor (MOSFET) is only recently commercially available in SiC. This delay is due to critical technology issues related to reliability and stability of the device, which still challenge many researchers all over the world. This thesis summarizes the main challenges of the SiC MOSFET fabrication process. State of the art technology modules like the gate stack formation, the drain/source ohmic contact formation, and the passivation layer deposition are considered and contributions of this work to the development of these technology modules is reported. The investigated technology modules are integrated into the complete fabrication process of vertical MOSFET devices. This MOSFET process was tested using cubic SiC (3C-SiC) and hexagonal SiC (4H-SiC) wafers and achieved results will be discussed.QC 2011041