Observation of single-carrier space-charge-limited flow in nitrogen-doped α-silicon carbide. I. I-V characteristics and impedance

This paper first reviews the properties of silicon carbide, in which polytypism is a salient feature. If a highly compensated insulating polytype is sandwiched between low resistive polytypes, space-charge injection will occur. The theory of space-charge-limited current flow in the presence of traps is reviewed and a somewhat different version of the standard theory is presented, which shows more clearly the ohmic and space-charge-limiting regimes. Close analytical parametric forms for I and V are obtained. Experimental data on I-V characteristics and impedance are presented for 52–300 K. Except at the highest temperature, four regimes are clearly visible in the I-V curves. A quantitative comparison with the theory is made and various transport quantities for α-SiC are deduced.