High-Quality Schottky and Ohmic Contacts in Planar 4H-SiC Metal Semiconductor Field-Effect Transistors and Device Performance

摘要

We have fabricated planar 4H-SiC,metal-semiconductor field-effect transistors(MESFETs)with high-quality metal/SiC contacts.To eliminate potential damage to the gate region caused by etching and simplify the device fabrication process,gate Schottky contacts were formed without any recess gate etching,and an ideality factor of 1.03 was obtained for these gate contacts.The interface state density between the contact metal and SiC was 5.7X10~12 cm~-2 eV~-1,which was found from the relationship between the barrier height and the metal work function.These results indicate that the interface was well controlled.Thus,a transconductance of 30 mS/mm was achieved with a 3-mum gate length as the performance figure of these MESFETs with high-quality metal/SiC contacts.Also,a low ohmic contact resistance of 1.2X10~-6 OMEGAcm~2 was obtained for the source and drain ohmic contacts by using ion implantation.