Semi-insulating 4$H$-SiC layers formed by the implantation of high-energy (53 MeV) argon ions into $n$-type epitaxial films

It is shown that 9-$\mu$m-thick semi-insulating surface layers can be formed in moderately doped $n$-type silicon carbide (donor concentration 2 $\times$ 10$^{16}$ cm$^{-3}$ via the comparatively low-dose (7 $\times$ 10$^{11}$ cm$^{-2}$) implantation of high-energy (53 MeV) argon ions. The free-carrier removal rate is estimated at $\sim$10$^4$ cm$^{-1}$. The resistivity of the semi-insulator is no less than 7 $\times$ 10$^{12}$ $\Omega$ cm. Analysis of the monopolar current of electron injection into the semi-insulator shows that the impurity-conductivity compensation is due to radiationinduced defects pinning the equilibrium Fermi level at a depth of 1.16 eV below the conduction-band bottom. The density of defect states at the Fermi level is 2.7 $\times$ 10$^{16}$ cm$^{2}$ эВ$^{-1}$.