Interface improvement of epitaxial 4H-SiC based Schottky didoes by selective heavy ion irradiation

Abstract

This work reports selective high-energy heavy ions irradiation for improving the interfacial properties of epitaxial SiC-based Schottky barrier diode (SBD). Ni/4H-nSiC(0001) SBDs have been fabricated and irradiated using 200 MeV silver ions at a fluence of 1 × 1012 ions/cm2 in selective and in blanket ways under same experimental conditions. Electrical performance of the blanket way-irradiated SBD was found almost destroyed. In stark contrast, barrier height is enhanced from 1.16 eV to 1.41 eV and ideality factor reduced from 1.81 to 1.76 in selectively irradiated SBD. Moreover, interface trap/defect states density has been reduced from 1.56 × 1013 eV−1 cm−2 to 6.47 × 1012 eV−1 cm−2 after selective irradiation of SBD. Role of heavy ions irradiation-induced electronic excitations in refinement of atomic-scale interfacial defects/disorders of the SBD and, hence, modification in its electrical performance has been discussed. Photoluminescence studies are also performed to get insight into the measured device performance.