We fabricated 4H-SiC vertical MOSFETs with contacts to the source, p-well and polycrystalline silicon (polysilicon) gate and these were simultaneously formed from a single material, using one deposition and a single contact annealing process. Typical specific contact resistances of 4.8×10 -5 cm 2 for the n + source region, 1.5×10 -6 cm 2 for the gate polysilicon and 5.2×10 -4 cm 2 for the p-well contact region were obtained using Al/Ni (Al~6%) as the contact metal. Also, the static characteristics of the vertical MOSFETs indicated that the MOS interface can withstand an even higher temperature process such as that used in ohmic-contact formation.
A novel processing technology for MESFETs is demonstrated on 4H-SiC for the first time in which the gate and source/drain contacts are simultaneously formed using a single contact material and without post-deposition annealing (PDA). Regulated DC I d -V ds characteristics clearly showing a linear region, a saturation region and a pinch-off state were obtained for the contact materials such as Ti and Ni. A TLM analysis revealed specific contact resistivity of ρ C = 2.7×10 -7 Ωcm 2 for Ti and 2.0×10 -6 Ωcm 2 for Ni. This structure could have a direct impact on furthering the miniaturization of MESFETs. It could also shorten the device fabrication process by eliminating the fabrication step for the source/drain contacts.
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 5.7 ϫ 10 12 cm Ϫ2 eV Ϫ1 , 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-µm gate length as the performance figure of these MESFETs with high-quality metal/SiC contacts. Also, a low ohmic contact resistance of 1.2 ϫ 10 Ϫ6 Ωcm 2 was obtained for the source and drain ohmic contacts by using ion implantation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.