Determination of the activation energy ε3 for impurity conduction in n-type 4H–SiC

Impurity conduction (or hopping conduction) has been observed in the more heavily n-type 4H–SiC samples by both temperature dependent resistivity measurements and thermal admittance spectroscopy. The measured activation energies ε3 for hopping were 4–5 meV and 2.3–3.0 meV, respectively. No evidence of hopping conduction was seen by either method in the sample where ND–NA<1018 cm−3. The thermal admittance spectrum of the lightly n-type sample showed the two nitrogen levels at 53 and 100 meV.