Characterization of phosphorus doped n-type 6H silicon carbide epitaxial layers produced by nuclear transmutation doping

Aluminum doped 6H-SiC epitaxial layers (p-type net doping: N-A-N-D=5.2 x 10(15) cm(-3), thickness 3 mu m) on a p(+) doped 6H-SiC substrate (N-A-N-D = 10(18) cm(-3)) were irradiated with neutrons in a nuclear reactor. The neutron fluences applied were 9.4 x 10(19), 3.5 x 10(20), and 6.4 x 10(20) cm(-2). The phosphorus impurity in SiC is produced by a nuclear (n, gamma) reaction with the decay of Si-31 to P-31. The irradiated samples were subsequently annealed at temperatures between 800 and 1850 degrees C. The annealing behavior was studied by low temperature photoluminescence, Fourier transform infrared spectroscopy, and Hall effect and I-V and C-V measurements. After the annealing process the 6H-SiC p-type epilayer changed to n type resulting in a pn junction within the material. The properties of the pn junction were characterized. (C) 1998 American Institute of Physics.