Metal Work-function and Doping-Concentration Dependent Barrier Height of Ni-Contacts to 4H-SiC with Metal-Embedded Nano-Particles

摘要

We investigated the effect of the metal work-function and doping concentration on the barrier height of Ni-contacts with embedded nano-particles (NPs) on 4H-SiC surfaces. Both n-type epitaxial layers with N_D=1×10~(16) cm~(-3), and layers doped by phosphorus implantation to a doping concentration of ～1×10~(19) cm~(-3) are used. The barrier height is reduced with increasing doping concentration and the silver (Ag) nano-particles (R～18.5 nm) further enhance the local electric field of the electrical contacts to 4H-SiC in comparison to gold (Au) nano-particles (R～20.2 nm). In the case of ion-implanted samples, the barrier height of the fabricated SiC diode structures with embedded Ag-NPs was significantly reduced by ～0.09 Ev and ～0.25 Ev compared to the samples with Au-NPs and the sample without NPs, respectively.